NEW FEATURES AND NEW FUNCTIONS

1 files changed, 161 insertions, 0 deletions

diff --git a/src/c/linearAlgebra/schur/dgschura.c b/src/c/linearAlgebra/schur/dgschura.c
new file mode 100644
index 00000000..f17da8c8
--- /dev/null
+++ b/src/c/linearAlgebra/schur/dgschura.c
@@ -0,0 +1,161 @@
+/* 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
+ */
+
+/*Fucntion to find generalised schur decomposition of given square matrices */
+#include "schur.h"
+#include "lapack.h"
+#include "stdlib.h"
+#include "string.h"
+#include <math.h>
+
+/*flag  --> 0: nothing
+		--> 1: continuous
+		--> 2: discrete
+*/
+
+lapack_logical selctg21( double* in1, double* in2, double* in3);
+lapack_logical selctg22( double* in1, double* in2, double* in3);
+
+double dgschura(double* in1, int size, double* in2, int flag, int nout, \
+			double* out1, double* out2, double* out3, double* out4)
+{
+	char JOBVSL = 'N';
+	char JOBVSR = 'N';
+	char SORT = 'N';
+	int SDIM = 0;
+	int LDVSL = size, LDVSR = size;
+    int LWORK = 8*size+16, INFO;
+	double *ALPHAR, *ALPHAI, *BETA, *VSL, *VSR, *WORK;
+	int *BWORK;
+	double ret = 0;
+	double *buf1, *buf2; /*input is copied to buf, since lapack function directly
+	modifies the input variable*/
+
+	/*Used incase of flag > 0*/ 
+	LAPACK_D_SELECT3 selctg = &selctg21;  
+
+	if(nout >= 2){
+		 JOBVSL = 'V';
+		 JOBVSR = 'V';
+		}
+	if(flag > 0) SORT = 'S';
+
+	buf1   = (double*) malloc((double) size*size*sizeof(double));
+	buf2   = (double*) malloc((double) size*size*sizeof(double));
+	ALPHAR = (double*) malloc((double) size*sizeof(double));
+	ALPHAI = (double*) malloc((double) size*sizeof(double));
+	BETA   = (double*) malloc((double) size*sizeof(double));
+	VSL = (double*) malloc((double) LDVSL*size*sizeof(double));
+	VSR = (double*) malloc((double) LDVSR*size*sizeof(double));
+	WORK = (double*) malloc((double) LWORK*sizeof(double));
+	BWORK = (int*) malloc((double) size*sizeof(double));
+
+
+	memcpy(buf1,in1,size*size*sizeof(double));
+	memcpy(buf2,in2,size*size*sizeof(double));
+
+	dgges_(&JOBVSL,&JOBVSR,&SORT,selctg,&size,buf1,&size,buf2,&size,&SDIM, \
+			ALPHAR,ALPHAI,BETA,VSL,&LDVSL,VSR,&LDVSR,WORK,&LWORK,BWORK,&INFO);
+
+	/*if (INFO != 0) 
+	{
+		out1 = NULL;
+		return 0;
+	}*/
+
+	if(nout == 1)
+	{
+		return(SDIM);
+	}
+	else if(nout == 2)
+	{
+		if(flag == 0)
+		{
+			/*copy in1 to out1 and in2 to out2*/
+			memcpy(out1,buf1,size*size*sizeof(double));
+			memcpy(out2,buf2,size*size*sizeof(double));
+		}
+		else
+		{
+			/*copy VSR to out1 and return SDIM */
+			memcpy(out1,VSR,size*size*sizeof(double));
+			ret = SDIM;
+		}
+	}
+	else if(nout == 3) 
+	{
+		/*copy VSL to out1, VSR to out2, return SDIM*/
+		memcpy(out1,VSL,size*size*sizeof(double));
+		memcpy(out2,VSR,size*size*sizeof(double));
+		ret = SDIM;
+	}
+	else if(nout == 4)
+	{
+		if(flag == 0)
+		{
+			/*copy in1 to out1 and in2 to out2*/
+			memcpy(out1,buf1,size*size*sizeof(double));
+			memcpy(out2,buf2,size*size*sizeof(double));
+			/*copy VSL to out3 and VSR to out4*/
+			memcpy(out3,VSL,size*size*sizeof(double));
+			memcpy(out4,VSR,size*size*sizeof(double));
+		}
+		else
+		{
+			/*copy in1 to out1 and in2 to out2*/
+			memcpy(out1,buf1,size*size*sizeof(double));
+			memcpy(out2,buf2,size*size*sizeof(double));
+			/*copy VSR to out3 and return SDIM*/
+			memcpy(out3,VSR,size*size*sizeof(double));
+			ret = SDIM;
+		}
+	}
+	else /*nout = 5*/
+	{
+		/*copy in1 to out1 and in2 to out2*/
+		memcpy(out1,buf1,size*size*sizeof(double));
+		memcpy(out2,buf2,size*size*sizeof(double));
+		/*copy VSL to out3 and VSR to out4*/
+		memcpy(out3,VSL,size*size*sizeof(double));
+		memcpy(out4,VSR,size*size*sizeof(double));
+		/*return SDIM*/
+		ret = SDIM;
+	}
+
+	free(buf1);
+	free(buf2);
+	free(VSL);
+	free(VSR);
+	free(ALPHAR);
+	free(ALPHAI);
+	free(BETA);
+	free(WORK);
+	free(BWORK);
+
+	return ret;
+}
+
+lapack_logical selctg21(double* in1, double* in2,  double* in3)
+{
+	if((sqrt(*in1**in1+*in2**in2)/ *in3) < 1)
+		return 1;
+	else 
+		return 0;
+}
+
+lapack_logical selctg22(double* in1, double* in2,  double* in3)
+{
+	if((sqrt(*in1**in1+*in2**in2)/ *in3) < 1)
+		return 1;
+	else 
+		return 0;
+}
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