1 files changed, 75 insertions, 0 deletions
diff --git a/src/c/linearAlgebra/balanc/dbalanca.c b/src/c/linearAlgebra/balanc/dbalanca.c
new file mode 100644
index 0000000..558c614
--- /dev/null
+++ b/src/c/linearAlgebra/balanc/dbalanca.c
@@ -0,0 +1,75 @@
+/* Copyright (C) 2017 - IIT Bombay - FOSSEE
+
+ This file must be used under the terms of the CeCILL.
+ This source file is licensed as described in the file COPYING, which
+ you should have received as part of this distribution.  The terms
+ are also available at
+ http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
+ Author: Siddhesh Wani
+ Organization: FOSSEE, IIT Bombay
+ Email: toolbox@scilab.in
+ */
+
+/*Funtion to balance given square matrix to improve its condition number*/
+#include "balanc.h"
+#include "lapack.h"
+#include "stdlib.h"
+#include "string.h"
+#include "eye.h"
+
+void dbalanca(double* in1, int rows, double* in2, double* out1, \
+		double* out2, double* out3, double* out4)
+{
+	char JOB = 'B';
+	char RSIDE = 'R';
+	char LSIDE = 'L';
+
+	int ILO, IHI, INFO;
+	double *buf1, *buf2, *LSCALE, *RSCALE;
+	double *LWORK;
+
+
+	if(in2 == NULL)
+	{
+		/*Single input matrix*/
+		buf1   = (double*) malloc((double) rows*rows*sizeof(double));
+		LSCALE = (double*) malloc((double) rows*sizeof(double));
+
+		/*copy input to temp buf as lapack function modifies input*/
+		memcpy(buf1,in1,rows*rows*sizeof(double));
+
+		dgebal_(&JOB,&rows,buf1,&rows,&ILO,&IHI,LSCALE,&INFO);
+		deyea(out2,rows,rows);
+		dgebak_(&JOB,&RSIDE,&rows,&ILO,&IHI,LSCALE,&rows,out2,&rows,&INFO);
+		
+		/*copy computed matrix to output*/
+		memcpy(out1,buf1,rows*rows*sizeof(double));
+	}
+	else
+	{
+		/*two matrices as inputs*/
+		buf1   = (double*) malloc((double) rows*rows*sizeof(double));
+		buf2   = (double*) malloc((double) rows*rows*sizeof(double));
+		LSCALE = (double*) malloc((double) rows*sizeof(double));
+		RSCALE = (double*) malloc((double) rows*sizeof(double));
+		LWORK  = (double*) malloc((double) 6*rows*sizeof(double));
+
+		/*copy input to temp buf as lapack function modifies input*/
+		memcpy(buf1,in1,rows*rows*sizeof(double));
+		memcpy(buf2,in2,rows*rows*sizeof(double));
+
+		dggbal_(&JOB,&rows,buf1,&rows,buf2,&rows,&ILO,&IHI,LSCALE,RSCALE, \
+					LWORK,INFO);
+		deyea(out3,rows,rows);
+		deyea(out4,rows,rows);
+
+		dgebak_(&JOB,&LSIDE,&rows,&ILO,&IHI,LSCALE,&rows,out3,&rows,&INFO);
+		dgebak_(&JOB,&RSIDE,&rows,&ILO,&IHI,LSCALE,&rows,out4,&rows,&INFO);
+
+		/*copy computed matrix to output*/
+		memcpy(out1,buf1,rows*rows*sizeof(double));
+		memcpy(out2,buf2,rows*rows*sizeof(double));
+
+	}
+
+}
+\ No newline at end of file