/* cbabk2.f -- translated by f2c (version 19961017). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" /* Subroutine */ int cbabk2_(integer *nm, integer *n, integer *low, integer * igh, doublereal *scale, integer *m, doublereal *zr, doublereal *zi) { /* System generated locals */ integer zr_dim1, zr_offset, zi_dim1, zi_offset, i__1, i__2; /* Local variables */ static integer i__, j, k; static doublereal s; static integer ii; /* THIS SUBROUTINE IS A TRANSLATION OF THE ALGOL PROCEDURE */ /* CBABK2, WHICH IS A COMPLEX VERSION OF BALBAK, */ /* NUM. MATH. 13, 293-304(1969) BY PARLETT AND REINSCH. */ /* HANDBOOK FOR AUTO. COMP., VOL.II-LINEAR ALGEBRA, 315-326(1971). */ /* THIS SUBROUTINE FORMS THE EIGENVECTORS OF A COMPLEX GENERAL */ /* MATRIX BY BACK TRANSFORMING THOSE OF THE CORRESPONDING */ /* BALANCED MATRIX DETERMINED BY CBAL. */ /* ON INPUT */ /* NM MUST BE SET TO THE ROW DIMENSION OF TWO-DIMENSIONAL */ /* ARRAY PARAMETERS AS DECLARED IN THE CALLING PROGRAM */ /* DIMENSION STATEMENT. */ /* N IS THE ORDER OF THE MATRIX. */ /* LOW AND IGH ARE INTEGERS DETERMINED BY CBAL. */ /* SCALE CONTAINS INFORMATION DETERMINING THE PERMUTATIONS */ /* AND SCALING FACTORS USED BY CBAL. */ /* M IS THE NUMBER OF EIGENVECTORS TO BE BACK TRANSFORMED. */ /* ZR AND ZI CONTAIN THE REAL AND IMAGINARY PARTS, */ /* RESPECTIVELY, OF THE EIGENVECTORS TO BE */ /* BACK TRANSFORMED IN THEIR FIRST M COLUMNS. */ /* ON OUTPUT */ /* ZR AND ZI CONTAIN THE REAL AND IMAGINARY PARTS, */ /* RESPECTIVELY, OF THE TRANSFORMED EIGENVECTORS */ /* IN THEIR FIRST M COLUMNS. */ /* QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW, */ /* MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY */ /* THIS VERSION DATED AUGUST 1983. */ /* ------------------------------------------------------------------ */ /* Parameter adjustments */ --scale; zi_dim1 = *nm; zi_offset = zi_dim1 + 1; zi -= zi_offset; zr_dim1 = *nm; zr_offset = zr_dim1 + 1; zr -= zr_offset; /* Function Body */ if (*m == 0) { goto L200; } if (*igh == *low) { goto L120; } i__1 = *igh; for (i__ = *low; i__ <= i__1; ++i__) { s = scale[i__]; /* .......... LEFT HAND EIGENVECTORS ARE BACK TRANSFORMED */ /* IF THE FOREGOING STATEMENT IS REPLACED BY */ /* S=1.0D0/SCALE(I). .......... */ i__2 = *m; for (j = 1; j <= i__2; ++j) { zr[i__ + j * zr_dim1] *= s; zi[i__ + j * zi_dim1] *= s; /* L100: */ } /* L110: */ } /* .......... FOR I=LOW-1 STEP -1 UNTIL 1, */ /* IGH+1 STEP 1 UNTIL N DO -- .......... */ L120: i__1 = *n; for (ii = 1; ii <= i__1; ++ii) { i__ = ii; if (i__ >= *low && i__ <= *igh) { goto L140; } if (i__ < *low) { i__ = *low - ii; } k = (integer) scale[i__]; if (k == i__) { goto L140; } i__2 = *m; for (j = 1; j <= i__2; ++j) { s = zr[i__ + j * zr_dim1]; zr[i__ + j * zr_dim1] = zr[k + j * zr_dim1]; zr[k + j * zr_dim1] = s; s = zi[i__ + j * zi_dim1]; zi[i__ + j * zi_dim1] = zi[k + j * zi_dim1]; zi[k + j * zi_dim1] = s; /* L130: */ } L140: ; } L200: return 0; } /* cbabk2_ */