diff --git a/blas/s_blas2_lib4.c b/blas/s_blas2_lib4.c
new file mode 100644
index 0000000..b7a947d
--- /dev/null
+++ b/blas/s_blas2_lib4.c
@@ -0,0 +1,1045 @@
+/**************************************************************************************************
+*                                                                                                 *
+* This file is part of BLASFEO.                                                                   *
+*                                                                                                 *
+* BLASFEO -- BLAS For Embedded Optimization.                                                      *
+* Copyright (C) 2016-2017 by Gianluca Frison.                                                     *
+* Developed at IMTEK (University of Freiburg) under the supervision of Moritz Diehl.              *
+* All rights reserved.                                                                            *
+*                                                                                                 *
+* HPMPC is free software; you can redistribute it and/or                                          *
+* modify it under the terms of the GNU Lesser General Public                                      *
+* License as published by the Free Software Foundation; either                                    *
+* version 2.1 of the License, or (at your option) any later version.                              *
+*                                                                                                 *
+* HPMPC is distributed in the hope that it will be useful,                                        *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of                                  *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                                            *
+* See the GNU Lesser General Public License for more details.                                     *
+*                                                                                                 *
+* You should have received a copy of the GNU Lesser General Public                                *
+* License along with HPMPC; if not, write to the Free Software                                    *
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA                  *
+*                                                                                                 *
+* Author: Gianluca Frison, giaf (at) dtu.dk                                                       *
+*                          gianluca.frison (at) imtek.uni-freiburg.de                             *
+*                                                                                                 *
+**************************************************************************************************/
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "../include/blasfeo_common.h"
+#include "../include/blasfeo_s_kernel.h"
+#include "../include/blasfeo_s_aux.h"
+
+
+
+
+#if defined(LA_HIGH_PERFORMANCE)
+
+
+
+void sgemv_n_libstr(int m, int n, float alpha, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, float beta, struct s_strvec *sy, int yi, struct s_strvec *sz, int zi)
+	{
+
+	if(m<0)
+		return;
+
+	const int bs = 4;
+
+	int i;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs + ai/bs*bs*sda;
+	float *x = sx->pa + xi;
+	float *y = sy->pa + yi;
+	float *z = sz->pa + zi;
+
+	i = 0;
+	// clean up at the beginning
+	if(ai%bs!=0)
+		{
+		kernel_sgemv_n_4_gen_lib4(n, &alpha, pA, x, &beta, y-ai%bs, z-ai%bs, ai%bs, m+ai%bs);
+		pA += bs*sda;
+		y += 4 - ai%bs;
+		z += 4 - ai%bs;
+		m -= 4 - ai%bs;
+		}
+	// main loop
+	for( ; i<m-3; i+=4)
+		{
+		kernel_sgemv_n_4_lib4(n, &alpha, &pA[i*sda], x, &beta, &y[i], &z[i]);
+		}
+	if(i<m)
+		{
+		kernel_sgemv_n_4_vs_lib4(n, &alpha, &pA[i*sda], x, &beta, &y[i], &z[i], m-i);
+		}
+		
+	return;
+
+	}
+
+
+
+void sgemv_t_libstr(int m, int n, float alpha, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, float beta, struct s_strvec *sy, int yi, struct s_strvec *sz, int zi)
+	{
+
+	if(n<=0)
+		return;
+	
+	const int bs = 4;
+
+	int i;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs + ai/bs*bs*sda + ai%bs;
+	float *x = sx->pa + xi;
+	float *y = sy->pa + yi;
+	float *z = sz->pa + zi;
+
+	if(ai%bs==0)
+		{
+		i = 0;
+		for( ; i<n-3; i+=4)
+			{
+			kernel_sgemv_t_4_lib4(m, &alpha, &pA[i*bs], sda, x, &beta, &y[i], &z[i]);
+			}
+		if(i<n)
+			{
+			kernel_sgemv_t_4_vs_lib4(m, &alpha, &pA[i*bs], sda, x, &beta, &y[i], &z[i], n-i);
+			}
+		}
+	else // TODO kernel 8
+		{
+		i = 0;
+		for( ; i<n; i+=4)
+			{
+			kernel_sgemv_t_4_gen_lib4(m, &alpha, ai%bs, &pA[i*bs], sda, x, &beta, &y[i], &z[i], n-i);
+			}
+		}
+	
+	return;
+
+	}
+
+
+
+void sgemv_nt_libstr(int m, int n, float alpha_n, float alpha_t, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx_n, int xi_n, struct s_strvec *sx_t, int xi_t, float beta_n, float beta_t, struct s_strvec *sy_n, int yi_n, struct s_strvec *sy_t, int yi_t, struct s_strvec *sz_n, int zi_n, struct s_strvec *sz_t, int zi_t)
+	{
+
+	if(ai!=0)
+		{
+		printf("\nsgemv_nt_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *x_n = sx_n->pa + xi_n;
+	float *x_t = sx_t->pa + xi_t;
+	float *y_n = sy_n->pa + yi_n;
+	float *y_t = sy_t->pa + yi_t;
+	float *z_n = sz_n->pa + zi_n;
+	float *z_t = sz_t->pa + zi_t;
+
+//	sgemv_nt_lib(m, n, alpha_n, alpha_t, pA, sda, x_n, x_t, beta_n, beta_t, y_n, y_t, z_n, z_t);
+
+//	if(m<=0 | n<=0)
+//		return;
+
+	int ii;
+
+	// copy and scale y_n int z_n
+	ii = 0;
+	for(; ii<m-3; ii+=4)
+		{
+		z_n[ii+0] = beta_n*y_n[ii+0];
+		z_n[ii+1] = beta_n*y_n[ii+1];
+		z_n[ii+2] = beta_n*y_n[ii+2];
+		z_n[ii+3] = beta_n*y_n[ii+3];
+		}
+	for(; ii<m; ii++)
+		{
+		z_n[ii+0] = beta_n*y_n[ii+0];
+		}
+	
+	ii = 0;
+	for(; ii<n-3; ii+=4)
+		{
+		kernel_sgemv_nt_4_lib4(m, &alpha_n, &alpha_t, pA+ii*bs, sda, x_n+ii, x_t, &beta_t, y_t+ii, z_n, z_t+ii);
+		}
+	if(ii<n)
+		{
+		kernel_sgemv_nt_4_vs_lib4(m, &alpha_n, &alpha_t, pA+ii*bs, sda, x_n+ii, x_t, &beta_t, y_t+ii, z_n, z_t+ii, n-ii);
+		}
+	
+		return;
+	}
+
+
+
+void ssymv_l_libstr(int m, int n, float alpha, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, float beta, struct s_strvec *sy, int yi, struct s_strvec *sz, int zi)
+	{
+
+	if(m<=0 | n<=0)
+		return;
+	
+	const int bs = 4;
+
+	int ii, n1;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs + ai/bs*bs*sda + ai%bs;
+	float *x = sx->pa + xi;
+	float *y = sy->pa + yi;
+	float *z = sz->pa + zi;
+
+	// copy and scale y int z
+	ii = 0;
+	for(; ii<m-3; ii+=4)
+		{
+		z[ii+0] = beta*y[ii+0];
+		z[ii+1] = beta*y[ii+1];
+		z[ii+2] = beta*y[ii+2];
+		z[ii+3] = beta*y[ii+3];
+		}
+	for(; ii<m; ii++)
+		{
+		z[ii+0] = beta*y[ii+0];
+		}
+	
+	// clean up at the beginning
+	if(ai%bs!=0) // 1, 2, 3
+		{
+		n1 = 4-ai%bs;
+		kernel_ssymv_l_4_gen_lib4(m, &alpha, ai%bs, &pA[0], sda, &x[0], &z[0], n<n1 ? n : n1);
+		pA += n1 + n1*bs + (sda-1)*bs;
+		x += n1;
+		z += n1;
+		m -= n1;
+		n -= n1;
+		}
+	// main loop
+	ii = 0;
+	for(; ii<n-3; ii+=4)
+		{
+		kernel_ssymv_l_4_lib4(m-ii, &alpha, &pA[ii*bs+ii*sda], sda, &x[ii], &z[ii]);
+		}
+	// clean up at the end
+	if(ii<n)
+		{
+		kernel_ssymv_l_4_gen_lib4(m-ii, &alpha, 0, &pA[ii*bs+ii*sda], sda, &x[ii], &z[ii], n-ii);
+		}
+	
+	return;
+	}
+
+
+
+// m >= n
+void strmv_lnn_libstr(int m, int n, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m<=0)
+		return;
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs + ai/bs*bs*sda + ai%bs;
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	if(m-n>0)
+		sgemv_n_libstr(m-n, n, 1.0, sA, ai+n, aj, sx, xi, 0.0, sz, zi+n, sz, zi+n);
+
+	float *pA2 = pA;
+	float *z2 = z;
+	int m2 = n;
+	int n2 = 0;
+	float *pA3, *x3;
+
+	float alpha = 1.0;
+	float beta = 1.0;
+
+	float zt[4];
+
+	int ii, jj, jj_end;
+
+	ii = 0;
+
+	if(ai%4!=0)
+		{
+		pA2 += sda*bs - ai%bs;
+		z2 += bs-ai%bs;
+		m2 -= bs-ai%bs;
+		n2 += bs-ai%bs;
+		}
+	
+	pA2 += m2/bs*bs*sda;
+	z2 += m2/bs*bs;
+	n2 += m2/bs*bs;
+
+	if(m2%bs!=0)
+		{
+		//
+		pA3 = pA2 + bs*n2;
+		x3 = x + n2;
+		zt[3] = pA3[3+bs*0]*x3[0] + pA3[3+bs*1]*x3[1] + pA3[3+bs*2]*x3[2] + pA3[3+bs*3]*x3[3];
+		zt[2] = pA3[2+bs*0]*x3[0] + pA3[2+bs*1]*x3[1] + pA3[2+bs*2]*x3[2];
+		zt[1] = pA3[1+bs*0]*x3[0] + pA3[1+bs*1]*x3[1];
+		zt[0] = pA3[0+bs*0]*x3[0];
+		kernel_sgemv_n_4_lib4(n2, &alpha, pA2, x, &beta, zt, zt);
+		for(jj=0; jj<m2%bs; jj++)
+			z2[jj] = zt[jj];
+		}
+	for(; ii<m2-3; ii+=4)
+		{
+		pA2 -= bs*sda;
+		z2 -= 4;
+		n2 -= 4;
+		pA3 = pA2 + bs*n2;
+		x3 = x + n2;
+		z2[3] = pA3[3+bs*0]*x3[0] + pA3[3+bs*1]*x3[1] + pA3[3+bs*2]*x3[2] + pA3[3+bs*3]*x3[3];
+		z2[2] = pA3[2+bs*0]*x3[0] + pA3[2+bs*1]*x3[1] + pA3[2+bs*2]*x3[2];
+		z2[1] = pA3[1+bs*0]*x3[0] + pA3[1+bs*1]*x3[1];
+		z2[0] = pA3[0+bs*0]*x3[0];
+		kernel_sgemv_n_4_lib4(n2, &alpha, pA2, x, &beta, z2, z2);
+		}
+	if(ai%4!=0)
+		{
+		if(ai%bs==1)
+			{
+			zt[2] = pA[2+bs*0]*x[0] + pA[2+bs*1]*x[1] + pA[2+bs*2]*x[2];
+			zt[1] = pA[1+bs*0]*x[0] + pA[1+bs*1]*x[1];
+			zt[0] = pA[0+bs*0]*x[0];
+			jj_end = 4-ai%bs<n ? 4-ai%bs : n;
+			for(jj=0; jj<jj_end; jj++)
+				z[jj] = zt[jj];
+			}
+		else if(ai%bs==2)
+			{
+			zt[1] = pA[1+bs*0]*x[0] + pA[1+bs*1]*x[1];
+			zt[0] = pA[0+bs*0]*x[0];
+			jj_end = 4-ai%bs<n ? 4-ai%bs : n;
+			for(jj=0; jj<jj_end; jj++)
+				z[jj] = zt[jj];
+			}
+		else // if (ai%bs==3)
+			{
+			z[0] = pA[0+bs*0]*x[0];
+			}
+		}
+
+	return;
+
+	}
+
+
+
+// m >= n
+void strmv_ltn_libstr(int m, int n, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m<=0)
+		return;
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs + ai/bs*bs*sda + ai%bs;
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	float xt[4];
+	float zt[4];
+
+	float alpha = 1.0;
+	float beta = 1.0;
+
+	int ii, jj, ll, ll_max;
+
+	jj = 0;
+
+	if(ai%bs!=0)
+		{
+
+		if(ai%bs==1)
+			{
+			ll_max = m-jj<3 ? m-jj : 3;
+			for(ll=0; ll<ll_max; ll++)
+				xt[ll] = x[ll];
+			for(; ll<3; ll++)
+				xt[ll] = 0.0;
+			zt[0] = pA[0+bs*0]*xt[0] + pA[1+bs*0]*xt[1] + pA[2+bs*0]*xt[2];
+			zt[1] = pA[1+bs*1]*xt[1] + pA[2+bs*1]*xt[2];
+			zt[2] = pA[2+bs*2]*xt[2];
+			pA += bs*sda - 1;
+			x += 3;
+			kernel_sgemv_t_4_lib4(m-3-jj, &alpha, pA, sda, x, &beta, zt, zt);
+			ll_max = n-jj<3 ? n-jj : 3;
+			for(ll=0; ll<ll_max; ll++)
+				z[ll] = zt[ll];
+			pA += bs*3;
+			z += 3;
+			jj += 3;
+			}
+		else if(ai%bs==2)
+			{
+			ll_max = m-jj<2 ? m-jj : 2;
+			for(ll=0; ll<ll_max; ll++)
+				xt[ll] = x[ll];
+			for(; ll<2; ll++)
+				xt[ll] = 0.0;
+			zt[0] = pA[0+bs*0]*xt[0] + pA[1+bs*0]*xt[1];
+			zt[1] = pA[1+bs*1]*xt[1];
+			pA += bs*sda - 2;
+			x += 2;
+			kernel_sgemv_t_4_lib4(m-2-jj, &alpha, pA, sda, x, &beta, zt, zt);
+			ll_max = n-jj<2 ? n-jj : 2;
+			for(ll=0; ll<ll_max; ll++)
+				z[ll] = zt[ll];
+			pA += bs*2;
+			z += 2;
+			jj += 2;
+			}
+		else // if(ai%bs==3)
+			{
+			ll_max = m-jj<1 ? m-jj : 1;
+			for(ll=0; ll<ll_max; ll++)
+				xt[ll] = x[ll];
+			for(; ll<1; ll++)
+				xt[ll] = 0.0;
+			zt[0] = pA[0+bs*0]*xt[0];
+			pA += bs*sda - 3;
+			x += 1;
+			kernel_sgemv_t_4_lib4(m-1-jj, &alpha, pA, sda, x, &beta, zt, zt);
+			ll_max = n-jj<1 ? n-jj : 1;
+			for(ll=0; ll<ll_max; ll++)
+				z[ll] = zt[ll];
+			pA += bs*1;
+			z += 1;
+			jj += 1;
+			}
+
+		}
+	
+	for(; jj<n-3; jj+=4)
+		{
+		zt[0] = pA[0+bs*0]*x[0] + pA[1+bs*0]*x[1] + pA[2+bs*0]*x[2] + pA[3+bs*0]*x[3];
+		zt[1] = pA[1+bs*1]*x[1] + pA[2+bs*1]*x[2] + pA[3+bs*1]*x[3];
+		zt[2] = pA[2+bs*2]*x[2] + pA[3+bs*2]*x[3];
+		zt[3] = pA[3+bs*3]*x[3];
+		pA += bs*sda;
+		x += 4;
+		kernel_sgemv_t_4_lib4(m-4-jj, &alpha, pA, sda, x, &beta, zt, z);
+		pA += bs*4;
+		z += 4;
+		}
+	if(jj<n)
+		{
+		ll_max = m-jj<4 ? m-jj : 4;
+		for(ll=0; ll<ll_max; ll++)
+			xt[ll] = x[ll];
+		for(; ll<4; ll++)
+			xt[ll] = 0.0;
+		zt[0] = pA[0+bs*0]*xt[0] + pA[1+bs*0]*xt[1] + pA[2+bs*0]*xt[2] + pA[3+bs*0]*xt[3];
+		zt[1] = pA[1+bs*1]*xt[1] + pA[2+bs*1]*xt[2] + pA[3+bs*1]*xt[3];
+		zt[2] = pA[2+bs*2]*xt[2] + pA[3+bs*2]*xt[3];
+		zt[3] = pA[3+bs*3]*xt[3];
+		pA += bs*sda;
+		x += 4;
+		kernel_sgemv_t_4_lib4(m-4-jj, &alpha, pA, sda, x, &beta, zt, zt);
+		for(ll=0; ll<n-jj; ll++)
+			z[ll] = zt[ll];
+//		pA += bs*4;
+//		z += 4;
+		}
+
+	return;
+
+	}
+
+
+
+void strmv_unn_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m<=0)
+		return;
+
+	if(ai!=0)
+		{
+		printf("\ndtrmv_unn_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	int i;
+	
+	i=0;
+	for(; i<m-3; i+=4)
+		{
+		kernel_strmv_un_4_lib4(m-i, pA, x, z);
+		pA += 4*sda+4*bs;
+		x  += 4;
+		z  += 4;
+		}
+	if(m>i)
+		{
+		if(m-i==1)
+			{
+			z[0] = pA[0+bs*0]*x[0];
+			}
+		else if(m-i==2)
+			{
+			z[0] = pA[0+bs*0]*x[0] + pA[0+bs*1]*x[1];
+			z[1] = pA[1+bs*1]*x[1];
+			}
+		else // if(m-i==3)
+			{
+			z[0] = pA[0+bs*0]*x[0] + pA[0+bs*1]*x[1] + pA[0+bs*2]*x[2];
+			z[1] = pA[1+bs*1]*x[1] + pA[1+bs*2]*x[2];
+			z[2] = pA[2+bs*2]*x[2];
+			}
+		}
+
+	return;
+
+	}
+
+
+
+void strmv_utn_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m<=0)
+		return;
+
+	if(ai!=0)
+		{
+		printf("\nstrmv_utn_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	int ii, idx;
+	
+	float *ptrA;
+	
+	ii=0;
+	idx = m/bs*bs;
+	if(m%bs!=0)
+		{
+		kernel_strmv_ut_4_vs_lib4(m, pA+idx*bs, sda, x, z+idx, m%bs);
+		ii += m%bs;
+		}
+	idx -= 4;
+	for(; ii<m; ii+=4)
+		{
+		kernel_strmv_ut_4_lib4(idx+4, pA+idx*bs, sda, x, z+idx);
+		idx -= 4;
+		}
+
+	return;
+
+	}
+
+
+
+void strsv_lnn_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m==0)
+		return;
+
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_lnn_libstr : m<0 : %d<0 *****\n", m);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_lnn_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_lnn_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_lnn_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_lnn_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_lnn_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+m > sA->n) printf("\n***** strsv_lnn_libstr : aj+m > col(A) : %d+%d > %d *****\n", aj, m, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_lnn_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_lnn_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+
+	if(ai!=0)
+		{
+		printf("\nstrsv_lnn_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *dA = sA->dA;
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	int ii;
+
+	if(ai==0 & aj==0)
+		{
+		if(sA->use_dA!=1)
+			{
+			sdiaex_lib(m, 1.0, ai, pA, sda, dA);
+			for(ii=0; ii<m; ii++)
+				dA[ii] = 1.0 / dA[ii];
+			sA->use_dA = 1;
+			}
+		}
+	else
+		{
+		sdiaex_lib(m, 1.0, ai, pA, sda, dA);
+		for(ii=0; ii<m; ii++)
+			dA[ii] = 1.0 / dA[ii];
+		sA->use_dA = 0;
+		}
+
+	int i;
+
+	if(x!=z)
+		{
+		for(i=0; i<m; i++)
+			z[i] = x[i];
+		}
+	
+	i = 0;
+	for( ; i<m-3; i+=4)
+		{
+		kernel_strsv_ln_inv_4_lib4(i, &pA[i*sda], &dA[i], z, &z[i], &z[i]);
+		}
+	if(i<m)
+		{
+		kernel_strsv_ln_inv_4_vs_lib4(i, &pA[i*sda], &dA[i], z, &z[i], &z[i], m-i, m-i);
+		i+=4;
+		}
+
+	return;
+
+	}
+
+
+
+void strsv_lnn_mn_libstr(int m, int n, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m==0 | n==0)
+		return;
+
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_lnn_mn_libstr : m<0 : %d<0 *****\n", m);
+	if(n<0) printf("\n****** strsv_lnn_mn_libstr : n<0 : %d<0 *****\n", n);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_lnn_mn_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_lnn_mn_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_lnn_mn_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_lnn_mn_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_lnn_mn_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+n > sA->n) printf("\n***** strsv_lnn_mn_libstr : aj+n > col(A) : %d+%d > %d *****\n", aj, n, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_lnn_mn_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_lnn_mn_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+
+	if(ai!=0)
+		{
+		printf("\nstrsv_lnn_mn_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *dA = sA->dA;
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	int ii;
+
+	if(ai==0 & aj==0)
+		{
+		if(sA->use_dA!=1)
+			{
+			sdiaex_lib(n, 1.0, ai, pA, sda, dA);
+			for(ii=0; ii<n; ii++)
+				dA[ii] = 1.0 / dA[ii];
+			sA->use_dA = 1;
+			}
+		}
+	else
+		{
+		sdiaex_lib(n, 1.0, ai, pA, sda, dA);
+		for(ii=0; ii<n; ii++)
+			dA[ii] = 1.0 / dA[ii];
+		sA->use_dA = 0;
+		}
+
+	if(m<n)
+		m = n;
+
+	float alpha = -1.0;
+	float beta = 1.0;
+
+	int i;
+
+	if(x!=z)
+		{
+		for(i=0; i<m; i++)
+			z[i] = x[i];
+		}
+	
+	i = 0;
+	for( ; i<n-3; i+=4)
+		{
+		kernel_strsv_ln_inv_4_lib4(i, &pA[i*sda], &dA[i], z, &z[i], &z[i]);
+		}
+	if(i<n)
+		{
+		kernel_strsv_ln_inv_4_vs_lib4(i, &pA[i*sda], &dA[i], z, &z[i], &z[i], m-i, n-i);
+		i+=4;
+		}
+	for( ; i<m-3; i+=4)
+		{
+		kernel_sgemv_n_4_lib4(n, &alpha, &pA[i*sda], z, &beta, &z[i], &z[i]);
+		}
+	if(i<m)
+		{
+		kernel_sgemv_n_4_vs_lib4(n, &alpha, &pA[i*sda], z, &beta, &z[i], &z[i], m-i);
+		i+=4;
+		}
+
+	return;
+
+	}
+
+
+
+void strsv_ltn_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m==0)
+		return;
+
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_ltn_libstr : m<0 : %d<0 *****\n", m);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_ltn_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_ltn_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_ltn_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_ltn_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_ltn_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+m > sA->n) printf("\n***** strsv_ltn_libstr : aj+m > col(A) : %d+%d > %d *****\n", aj, m, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_ltn_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_ltn_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+
+	if(ai!=0)
+		{
+		printf("\nstrsv_ltn_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *dA = sA->dA;
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	int ii;
+
+	if(ai==0 & aj==0)
+		{
+		if(sA->use_dA!=1)
+			{
+			sdiaex_lib(m, 1.0, ai, pA, sda, dA);
+			for(ii=0; ii<m; ii++)
+				dA[ii] = 1.0 / dA[ii];
+			sA->use_dA = 1;
+			}
+		}
+	else
+		{
+		sdiaex_lib(m, 1.0, ai, pA, sda, dA);
+		for(ii=0; ii<m; ii++)
+			dA[ii] = 1.0 / dA[ii];
+		sA->use_dA = 0;
+		}
+
+	int i;
+	
+	if(x!=z)
+		for(i=0; i<m; i++)
+			z[i] = x[i];
+			
+	i=0;
+	if(m%4==1)
+		{
+		kernel_strsv_lt_inv_1_lib4(i+1, &pA[m/bs*bs*sda+(m-i-1)*bs], sda, &dA[m-i-1], &z[m-i-1], &z[m-i-1], &z[m-i-1]);
+		i++;
+		}
+	else if(m%4==2)
+		{
+		kernel_strsv_lt_inv_2_lib4(i+2, &pA[m/bs*bs*sda+(m-i-2)*bs], sda, &dA[m-i-2], &z[m-i-2], &z[m-i-2], &z[m-i-2]);
+		i+=2;
+		}
+	else if(m%4==3)
+		{
+		kernel_strsv_lt_inv_3_lib4(i+3, &pA[m/bs*bs*sda+(m-i-3)*bs], sda, &dA[m-i-3], &z[m-i-3], &z[m-i-3], &z[m-i-3]);
+		i+=3;
+		}
+	for(; i<m-3; i+=4)
+		{
+		kernel_strsv_lt_inv_4_lib4(i+4, &pA[(m-i-4)/bs*bs*sda+(m-i-4)*bs], sda, &dA[m-i-4], &z[m-i-4], &z[m-i-4], &z[m-i-4]);
+		}
+
+	return;
+
+	}
+
+
+
+void strsv_ltn_mn_libstr(int m, int n, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+
+	if(m==0)
+		return;
+
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_ltn_mn_libstr : m<0 : %d<0 *****\n", m);
+	if(n<0) printf("\n****** strsv_ltn_mn_libstr : n<0 : %d<0 *****\n", n);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_ltn_mn_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_ltn_mn_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_ltn_mn_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_ltn_mn_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_ltn_mn_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+n > sA->n) printf("\n***** strsv_ltn_mn_libstr : aj+n > col(A) : %d+%d > %d *****\n", aj, n, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_ltn_mn_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_ltn_mn_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+
+	if(ai!=0)
+		{
+		printf("\nstrsv_ltn_mn_libstr: feature not implemented yet: ai=%d\n", ai);
+		exit(1);
+		}
+
+	const int bs = 4;
+
+	int sda = sA->cn;
+	float *pA = sA->pA + aj*bs; // TODO ai
+	float *dA = sA->dA;
+	float *x = sx->pa + xi;
+	float *z = sz->pa + zi;
+
+	int ii;
+
+	if(ai==0 & aj==0)
+		{
+		if(sA->use_dA!=1)
+			{
+			sdiaex_lib(n, 1.0, ai, pA, sda, dA);
+			for(ii=0; ii<n; ii++)
+				dA[ii] = 1.0 / dA[ii];
+			sA->use_dA = 1;
+			}
+		}
+	else
+		{
+		sdiaex_lib(n, 1.0, ai, pA, sda, dA);
+		for(ii=0; ii<n; ii++)
+			dA[ii] = 1.0 / dA[ii];
+		sA->use_dA = 0;
+		}
+
+	if(n>m)
+		n = m;
+	
+	int i;
+	
+	if(x!=z)
+		for(i=0; i<m; i++)
+			z[i] = x[i];
+			
+	i=0;
+	if(n%4==1)
+		{
+		kernel_strsv_lt_inv_1_lib4(m-n+i+1, &pA[n/bs*bs*sda+(n-i-1)*bs], sda, &dA[n-i-1], &z[n-i-1], &z[n-i-1], &z[n-i-1]);
+		i++;
+		}
+	else if(n%4==2)
+		{
+		kernel_strsv_lt_inv_2_lib4(m-n+i+2, &pA[n/bs*bs*sda+(n-i-2)*bs], sda, &dA[n-i-2], &z[n-i-2], &z[n-i-2], &z[n-i-2]);
+		i+=2;
+		}
+	else if(n%4==3)
+		{
+		kernel_strsv_lt_inv_3_lib4(m-n+i+3, &pA[n/bs*bs*sda+(n-i-3)*bs], sda, &dA[n-i-3], &z[n-i-3], &z[n-i-3], &z[n-i-3]);
+		i+=3;
+		}
+	for(; i<n-3; i+=4)
+		{
+		kernel_strsv_lt_inv_4_lib4(m-n+i+4, &pA[(n-i-4)/bs*bs*sda+(n-i-4)*bs], sda, &dA[n-i-4], &z[n-i-4], &z[n-i-4], &z[n-i-4]);
+		}
+
+	return;
+
+	}
+
+
+
+void strsv_lnu_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+	if(m==0)
+		return;
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_lnu_libstr : m<0 : %d<0 *****\n", m);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_lnu_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_lnu_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_lnu_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_lnu_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_lnu_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+m > sA->n) printf("\n***** strsv_lnu_libstr : aj+m > col(A) : %d+%d > %d *****\n", aj, m, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_lnu_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_lnu_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+	printf("\n***** strsv_lnu_libstr : feature not implemented yet *****\n");
+	exit(1);
+	}
+
+
+
+void strsv_ltu_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+	if(m==0)
+		return;
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_ltu_libstr : m<0 : %d<0 *****\n", m);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_ltu_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_ltu_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_ltu_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_ltu_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_ltu_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+m > sA->n) printf("\n***** strsv_ltu_libstr : aj+m > col(A) : %d+%d > %d *****\n", aj, m, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_ltu_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_ltu_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+	printf("\n***** strsv_ltu_libstr : feature not implemented yet *****\n");
+	exit(1);
+	}
+
+
+
+void strsv_unn_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+	if(m==0)
+		return;
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_unn_libstr : m<0 : %d<0 *****\n", m);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_unn_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_unn_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_unn_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_unn_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_unn_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+m > sA->n) printf("\n***** strsv_unn_libstr : aj+m > col(A) : %d+%d > %d *****\n", aj, m, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_unn_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_unn_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+	printf("\n***** strsv_unn_libstr : feature not implemented yet *****\n");
+	exit(1);
+	}
+
+
+
+void strsv_utn_libstr(int m, struct s_strmat *sA, int ai, int aj, struct s_strvec *sx, int xi, struct s_strvec *sz, int zi)
+	{
+	if(m==0)
+		return;
+#if defined(DIM_CHECK)
+	// non-negative size
+	if(m<0) printf("\n****** strsv_utn_libstr : m<0 : %d<0 *****\n", m);
+	// non-negative offset
+	if(ai<0) printf("\n****** strsv_utn_libstr : ai<0 : %d<0 *****\n", ai);
+	if(aj<0) printf("\n****** strsv_utn_libstr : aj<0 : %d<0 *****\n", aj);
+	if(xi<0) printf("\n****** strsv_utn_libstr : xi<0 : %d<0 *****\n", xi);
+	if(zi<0) printf("\n****** strsv_utn_libstr : zi<0 : %d<0 *****\n", zi);
+	// inside matrix
+	// A: m x k
+	if(ai+m > sA->m) printf("\n***** strsv_utn_libstr : ai+m > row(A) : %d+%d > %d *****\n", ai, m, sA->m);
+	if(aj+m > sA->n) printf("\n***** strsv_utn_libstr : aj+m > col(A) : %d+%d > %d *****\n", aj, m, sA->n);
+	// x: m
+	if(xi+m > sx->m) printf("\n***** strsv_utn_libstr : xi+m > size(x) : %d+%d > %d *****\n", xi, m, sx->m);
+	// z: m
+	if(zi+m > sz->m) printf("\n***** strsv_utn_libstr : zi+m > size(z) : %d+%d > %d *****\n", zi, m, sz->m);
+#endif
+	printf("\n***** strsv_utn_libstr : feature not implemented yet *****\n");
+	exit(1);
+	}
+
+
+
+#else
+
+#error : wrong LA choice
+
+#endif