From 681fe5c15be0a3a29dc9fdfa30142916a2ce6675 Mon Sep 17 00:00:00 2001
From: Sandeep Gupta
Date: Tue, 20 Jun 2017 17:18:04 +0530
Subject: 20-06-17

---
 src/c/linearAlgebra/spec/dspec1a.c | 151 +++++++++++++++++++++++++++++++++++--
 1 file changed, 143 insertions(+), 8 deletions(-)

(limited to 'src/c/linearAlgebra/spec')

diff --git a/src/c/linearAlgebra/spec/dspec1a.c b/src/c/linearAlgebra/spec/dspec1a.c
index 069454d..28440be 100644
--- a/src/c/linearAlgebra/spec/dspec1a.c
+++ b/src/c/linearAlgebra/spec/dspec1a.c
@@ -12,30 +12,165 @@
 
 /*This function finds the hessenberg form of a matrix A.*/
 
-#include "hess.h"
+#include "spec.h"
 #include <stdio.h>
 #include "string.h"
 #include "stdlib.h"
 #include "lapack.h"
 #include "matrixTranspose.h"
 #include "matrixMultiplication.h"
+#include "doubleComplex.h"
 
-void dspec1a(double *in1,double *in2,int size,int nout,double *out1,double *out2,double *out3,double *out4){
+extern int dggev_(char *,char *,int *,double *,int *,double *,int *,double *,double *,double *,double *,int *,double *,int *,double *,int *,int *);
+
+void assembleEigenvectorsInPlace(int N,double *ALPHAI,double *EVreal,double *EVimg){
+	int j,i;
+	j=0;
+	while(j<N){
+		if(ALPHAI[j] == 0){
+			//printf(" * ");
+			j+=1;	
+		}	
+		else{	
+			int ij;
+			int ij1;
+			for(i=0;i<N;i++){
+				ij = i+j*N;
+				ij1 = i+(j+1)*N;	
+				EVimg[ij] = EVreal[ij1];
+				EVimg[ij1] = -EVreal[ij1];	
+				EVreal[ij1] = EVreal[ij];
+			}
+			j+=2;						
+		}
+	}
+}
+
+void dspec1a(double *in1,double *in2,int size,int nout,doubleComplex *out1,double *out2,doubleComplex *out3,doubleComplex *out4){
+	
+	int i,j;
 	char JOBVL;
 	char JOBVR;
-	int N;
+	int N=size;
+	
 	double *A;
-	int LDA;
+	int LDA=N;
+	A = (double *)malloc(N*N*sizeof(double));	
+	memcpy(A,in1,N*N*sizeof(double));
+	
 	double *B;
-	int LDA;
+	int LDB=N;
+	B = (double *)malloc(N*N*sizeof(double));
+	memcpy(B,in2,N*N*sizeof(double));	
+	
 	double *ALPHAR;
+	ALPHAR = (double *)malloc(N*sizeof(double));
+	
 	double *ALPHAI;
+	ALPHAI = (double *)malloc(N*sizeof(double));
+		
 	double *BETA;
+	BETA = (double *)malloc(N*sizeof(double));
+	
 	double *VL;
-	int LDVL;
+	VL = (double *)malloc(N*N*sizeof(double));
+	
+	int LDVL=N;
+
 	double *VR;
-	int LDVR;
+	VR = (double *)malloc(N*N*sizeof(double));
+	int LDVR=N;
+	
+	int LWORK=8*N;
+
 	double *WORK;
-	int LWORK;
+	WORK = (double *)malloc(LWORK*sizeof(double));
+	
 	int INFO;
+	if(nout == 1){			/*out1 = spec(A,B)*/
+		JOBVL = 'N';
+		JOBVR = 'N';
+		dggev_(&JOBVL,&JOBVR,&N,A,&LDA,B,&LDB,ALPHAR,ALPHAI,BETA,VL,&LDVL,VR,&LDVR,WORK,&LWORK,&INFO);
+		for(i=0;i<N;i++){
+			out1[i] = DoubleComplex(ALPHAR[i]/BETA[i],ALPHAI[i]/BETA[i]);
+		}			
+	}
+	else if(nout == 2){		/*[out1,out2] = spec(A,B)*/
+		JOBVL = 'N';
+		JOBVR = 'N';
+		dggev_(&JOBVL,&JOBVR,&N,A,&LDA,B,&LDB,ALPHAR,ALPHAI,BETA,VL,&LDVL,VR,&LDVR,WORK,&LWORK,&INFO);
+		for(i=0;i<N;i++){
+			out1[i] = DoubleComplex(ALPHAR[i],ALPHAI[i]);		
+		}
+		memcpy(out2,BETA,N*sizeof(double));
+	}
+	else if(nout == 3){	 /* [out1,out2,out3] = spec(A,B) */
+		JOBVL = 'N';
+		JOBVR = 'V';	
+		dggev_(&JOBVL,&JOBVR,&N,A,&LDA,B,&LDB,ALPHAR,ALPHAI,BETA,VL,&LDVL,VR,&LDVR,WORK,&LWORK,&INFO);
+		for(i=0;i<N;i++){
+			out1[i] = DoubleComplex(ALPHAR[i],ALPHAI[i]);		
+		}	
+		memcpy(out2,BETA,N*sizeof(double));
+		
+		/*Because lapack routine doesn't give result in actual format, \
+			so we have to change the VR little-bit and then return the function */
+		
+		/*See the Scilab code || see the lapack subroutine libary - DGGEV where \
+			it is very explantory and explains all this.			
+		*/
+		double *EVimg;
+		EVimg = (double *)malloc(N*N*sizeof(double));
+		for(i=0;i<N;i++){
+			for(j=0;j<N;j++){
+				EVimg[i+j*N] = 0;					
+			}		
+		}		
+		assembleEigenvectorsInPlace(N,ALPHAI,VR,EVimg);		
+		for(i=0;i<N;i++){
+			for(j=0;j<N;j++){
+				out3[i+j*N] = DoubleComplex(VR[i+j*N],EVimg[i+j*N]);			
+			}		
+		}
+	}
+	else if(nout == 4){
+		JOBVL = 'V';
+		JOBVR = 'V';	
+
+		dggev_(&JOBVL,&JOBVR,&N,A,&LDA,B,&LDB,ALPHAR,ALPHAI,BETA,VL,&LDVL,VR,&LDVR,WORK,&LWORK,&INFO);
+
+		for(i=0;i<N;i++){
+			out1[i] = DoubleComplex(ALPHAR[i],ALPHAI[i]);		
+		}	
+
+		memcpy(out2,BETA,N*sizeof(double));
+		
+		double *EVimg;
+		EVimg = (double *)malloc(N*N*sizeof(double));
+		for(i=0;i<N;i++){
+			for(j=0;j<N;j++){
+				EVimg[i+j*N] = 0;					
+			}		
+		}		
+		assembleEigenvectorsInPlace(N,ALPHAI,VR,EVimg);		
+		for(i=0;i<N;i++){
+			for(j=0;j<N;j++){
+				out4[i+j*N] = DoubleComplex(VR[i+j*N],EVimg[i+j*N]);			
+			}		
+		}		
+		
+		double *EVimg1;
+		EVimg1 = (double *)malloc(N*N*sizeof(double));
+		for(i=0;i<N;i++){
+			for(j=0;j<N;j++){
+				EVimg1[i+j*N] = 0;			
+			}		
+		}		
+		assembleEigenvectorsInPlace(N,ALPHAI,VL,EVimg1);
+		for(i=0;i<N;i++){
+			for(j=0;j<N;j++){
+				out3[i+j*N] = DoubleComplex(VL[i+j*N],EVimg1[i+j*N]);			
+			}		
+		}
+	}
 }
-- 
cgit