text: #include "blaswrap.h"
  #include "f2c.h"
  
  /* Subroutine */ int dtrsm_(char *side, char *uplo, char *transa, char *diag, 
  	integer *m, integer *n, doublereal *alpha, doublereal *a, integer *
  	lda, doublereal *b, integer *ldb)
  {
      /* System generated locals */
      integer a_dim1, a_offset, b_dim1, b_offset, i__1, i__2, i__3;
      /* Local variables */
      static integer info;
      static doublereal temp;
      static integer i__, j, k;
      static logical lside;
      extern logical lsame_(char *, char *);
      static integer nrowa;
      static logical upper;
      extern /* Subroutine */ int xerbla_(char *, integer *);
      static logical nounit;
  #define a_ref(a_1,a_2) a[(a_2)*a_dim1 + a_1]
  #define b_ref(a_1,a_2) b[(a_2)*b_dim1 + a_1]
  /*  Purpose   
      =======   
      DTRSM  solves one of the matrix equations   
         op( A )*X = alpha*B,   or   X*op( A ) = alpha*B,   
      where alpha is a scalar, X and B are m by n matrices, A is a unit, or   
      non-unit,  upper or lower triangular matrix  and  op( A )  is one  of   
         op( A ) = A   or   op( A ) = A'.   
      The matrix X is overwritten on B.   
      Parameters   
      ==========   
      SIDE   - CHARACTER*1.   
               On entry, SIDE specifies whether op( A ) appears on the left   
               or right of X as follows:   
                  SIDE = 'L' or 'l'   op( A )*X = alpha*B.   
                  SIDE = 'R' or 'r'   X*op( A ) = alpha*B.   
               Unchanged on exit.   
      UPLO   - CHARACTER*1.   
               On entry, UPLO specifies whether the matrix A is an upper or   
               lower triangular matrix as follows:   
                  UPLO = 'U' or 'u'   A is an upper triangular matrix.   
                  UPLO = 'L' or 'l'   A is a lower triangular matrix.   
               Unchanged on exit.   
      TRANSA - CHARACTER*1.   
               On entry, TRANSA specifies the form of op( A ) to be used in   
               the matrix multiplication as follows:   
                  TRANSA = 'N' or 'n'   op( A ) = A.   
                  TRANSA = 'T' or 't'   op( A ) = A'.   
                  TRANSA = 'C' or 'c'   op( A ) = A'.   
               Unchanged on exit.   
      DIAG   - CHARACTER*1.   
               On entry, DIAG specifies whether or not A is unit triangular   
               as follows:   
                  DIAG = 'U' or 'u'   A is assumed to be unit triangular.   
                  DIAG = 'N' or 'n'   A is not assumed to be unit   
                                      triangular.   
               Unchanged on exit.   
      M      - INTEGER.   
               On entry, M specifies the number of rows of B. M must be at   
               least zero.   
               Unchanged on exit.   
      N      - INTEGER.   
               On entry, N specifies the number of columns of B.  N must be   
               at least zero.   
               Unchanged on exit.   
      ALPHA  - DOUBLE PRECISION.   
               On entry,  ALPHA specifies the scalar  alpha. When  alpha is   
               zero then  A is not referenced and  B need not be set before   
               entry.   
               Unchanged on exit.   
      A      - DOUBLE PRECISION array of DIMENSION ( LDA, k ), where k is m   
               when  SIDE = 'L' or 'l'  and is  n  when  SIDE = 'R' or 'r'.   
               Before entry  with  UPLO = 'U' or 'u',  the  leading  k by k   
               upper triangular part of the array  A must contain the upper   
               triangular matrix  and the strictly lower triangular part of   
               A is not referenced.   
               Before entry  with  UPLO = 'L' or 'l',  the  leading  k by k   
               lower triangular part of the array  A must contain the lower   
               triangular matrix  and the strictly upper triangular part of   
               A is not referenced.   
               Note that when  DIAG = 'U' or 'u',  the diagonal elements of   
               A  are not referenced either,  but are assumed to be  unity.   
               Unchanged on exit.   
      LDA    - INTEGER.   
               On entry, LDA specifies the first dimension of A as declared   
               in the calling (sub) program.  When  SIDE = 'L' or 'l'  then   
               LDA  must be at least  max( 1, m ),  when  SIDE = 'R' or 'r'   
               then LDA must be at least max( 1, n ).   
               Unchanged on exit.   
      B      - DOUBLE PRECISION array of DIMENSION ( LDB, n ).   
               Before entry,  the leading  m by n part of the array  B must   
               contain  the  right-hand  side  matrix  B,  and  on exit  is   
               overwritten by the solution matrix  X.   
      LDB    - INTEGER.   
               On entry, LDB specifies the first dimension of B as declared   
               in  the  calling  (sub)  program.   LDB  must  be  at  least   
               max( 1, m ).   
               Unchanged on exit.   
      Level 3 Blas routine.   
      -- Written on 8-February-1989.   
         Jack Dongarra, Argonne National Laboratory.   
         Iain Duff, AERE Harwell.   
         Jeremy Du Croz, Numerical Algorithms Group Ltd.   
         Sven Hammarling, Numerical Algorithms Group Ltd.   
         Test the input parameters.   
         Parameter adjustments */
      a_dim1 = *lda;
      a_offset = 1 + a_dim1 * 1;
      a -= a_offset;
      b_dim1 = *ldb;
      b_offset = 1 + b_dim1 * 1;
      b -= b_offset;
      /* Function Body */
      lside = lsame_(side, "L");
      if (lside) {
  	nrowa = *m;
      } else {
  	nrowa = *n;
      }
      nounit = lsame_(diag, "N");
      upper = lsame_(uplo, "U");
      info = 0;
      if (! lside && ! lsame_(side, "R")) {
  	info = 1;
      } else if (! upper && ! lsame_(uplo, "L")) {
  	info = 2;
      } else if (! lsame_(transa, "N") && ! lsame_(transa,
  	     "T") && ! lsame_(transa, "C")) {
  	info = 3;
      } else if (! lsame_(diag, "U") && ! lsame_(diag, 
  	    "N")) {
  	info = 4;
      } else if (*m < 0) {
  	info = 5;
      } else if (*n < 0) {
  	info = 6;
      } else if (*lda < max(1,nrowa)) {
  	info = 9;
      } else if (*ldb < max(1,*m)) {
  	info = 11;
      }
      if (info != 0) {
  	xerbla_("DTRSM ", &info);
  	return 0;
      }
  /*     Quick return if possible. */
      if (*n == 0) {
  	return 0;
      }
  /*     And when  alpha.eq.zero. */
      if (*alpha == 0.) {
  	i__1 = *n;
  	for (j = 1; j <= i__1; ++j) {
  	    i__2 = *m;
  	    for (i__ = 1; i__ <= i__2; ++i__) {
  		b_ref(i__, j) = 0.;
  /* L10: */
  	    }
  /* L20: */
  	}
  	return 0;
      }
  /*     Start the operations. */
      if (lside) {
  	if (lsame_(transa, "N")) {
  /*           Form  B := alpha*inv( A )*B. */
  	    if (upper) {
  		i__1 = *n;
  		for (j = 1; j <= i__1; ++j) {
  		    if (*alpha != 1.) {
  			i__2 = *m;
  			for (i__ = 1; i__ <= i__2; ++i__) {
  			    b_ref(i__, j) = *alpha * b_ref(i__, j);
  /* L30: */
  			}
  		    }
  		    for (k = *m; k >= 1; --k) {
  			if (b_ref(k, j) != 0.) {
  			    if (nounit) {
  				b_ref(k, j) = b_ref(k, j) / a_ref(k, k);
  			    }
  			    i__2 = k - 1;
  			    for (i__ = 1; i__ <= i__2; ++i__) {
  				b_ref(i__, j) = b_ref(i__, j) - b_ref(k, j) * 
  					a_ref(i__, k);
  /* L40: */
  			    }
  			}
  /* L50: */
  		    }
  /* L60: */
  		}
  	    } else {
  		i__1 = *n;
  		for (j = 1; j <= i__1; ++j) {
  		    if (*alpha != 1.) {
  			i__2 = *m;
  			for (i__ = 1; i__ <= i__2; ++i__) {
  			    b_ref(i__, j) = *alpha * b_ref(i__, j);
  /* L70: */
  			}
  		    }
  		    i__2 = *m;
  		    for (k = 1; k <= i__2; ++k) {
  			if (b_ref(k, j) != 0.) {
  			    if (nounit) {
  				b_ref(k, j) = b_ref(k, j) / a_ref(k, k);
  			    }
  			    i__3 = *m;
  			    for (i__ = k + 1; i__ <= i__3; ++i__) {
  				b_ref(i__, j) = b_ref(i__, j) - b_ref(k, j) * 
  					a_ref(i__, k);
  /* L80: */
  			    }
  			}
  /* L90: */
  		    }
  /* L100: */
  		}
  	    }
  	} else {
  /*           Form  B := alpha*inv( A' )*B. */
  	    if (upper) {
  		i__1 = *n;
  		for (j = 1; j <= i__1; ++j) {
  		    i__2 = *m;
  		    for (i__ = 1; i__ <= i__2; ++i__) {
  			temp = *alpha * b_ref(i__, j);
  			i__3 = i__ - 1;
  			for (k = 1; k <= i__3; ++k) {
  			    temp -= a_ref(k, i__) * b_ref(k, j);
  /* L110: */
  			}
  			if (nounit) {
  			    temp /= a_ref(i__, i__);
  			}
  			b_ref(i__, j) = temp;
  /* L120: */
  		    }
  /* L130: */
  		}
  	    } else {
  		i__1 = *n;
  		for (j = 1; j <= i__1; ++j) {
  		    for (i__ = *m; i__ >= 1; --i__) {
  			temp = *alpha * b_ref(i__, j);
  			i__2 = *m;
  			for (k = i__ + 1; k <= i__2; ++k) {
  			    temp -= a_ref(k, i__) * b_ref(k, j);
  /* L140: */
  			}
  			if (nounit) {
  			    temp /= a_ref(i__, i__);
  			}
  			b_ref(i__, j) = temp;
  /* L150: */
  		    }
  /* L160: */
  		}
  	    }
  	}
      } else {
  	if (lsame_(transa, "N")) {
  /*           Form  B := alpha*B*inv( A ). */
  	    if (upper) {
  		i__1 = *n;
  		for (j = 1; j <= i__1; ++j) {
  		    if (*alpha != 1.) {
  			i__2 = *m;
  			for (i__ = 1; i__ <= i__2; ++i__) {
  			    b_ref(i__, j) = *alpha * b_ref(i__, j);
  /* L170: */
  			}
  		    }
  		    i__2 = j - 1;
  		    for (k = 1; k <= i__2; ++k) {
  			if (a_ref(k, j) != 0.) {
  			    i__3 = *m;
  			    for (i__ = 1; i__ <= i__3; ++i__) {
  				b_ref(i__, j) = b_ref(i__, j) - a_ref(k, j) * 
  					b_ref(i__, k);
  /* L180: */
  			    }
  			}
  /* L190: */
  		    }
  		    if (nounit) {
  			temp = 1. / a_ref(j, j);
  			i__2 = *m;
  			for (i__ = 1; i__ <= i__2; ++i__) {
  			    b_ref(i__, j) = temp * b_ref(i__, j);
  /* L200: */
  			}
  		    }
  /* L210: */
  		}
  	    } else {
  		for (j = *n; j >= 1; --j) {
  		    if (*alpha != 1.) {
  			i__1 = *m;
  			for (i__ = 1; i__ <= i__1; ++i__) {
  			    b_ref(i__, j) = *alpha * b_ref(i__, j);
  /* L220: */
  			}
  		    }
  		    i__1 = *n;
  		    for (k = j + 1; k <= i__1; ++k) {
  			if (a_ref(k, j) != 0.) {
  			    i__2 = *m;
  			    for (i__ = 1; i__ <= i__2; ++i__) {
  				b_ref(i__, j) = b_ref(i__, j) - a_ref(k, j) * 
  					b_ref(i__, k);
  /* L230: */
  			    }
  			}
  /* L240: */
  		    }
  		    if (nounit) {
  			temp = 1. / a_ref(j, j);
  			i__1 = *m;
  			for (i__ = 1; i__ <= i__1; ++i__) {
  			    b_ref(i__, j) = temp * b_ref(i__, j);
  /* L250: */
  			}
  		    }
  /* L260: */
  		}
  	    }
  	} else {
  /*           Form  B := alpha*B*inv( A' ). */
  	    if (upper) {
  		for (k = *n; k >= 1; --k) {
  		    if (nounit) {
  			temp = 1. / a_ref(k, k);
  			i__1 = *m;
  			for (i__ = 1; i__ <= i__1; ++i__) {
  			    b_ref(i__, k) = temp * b_ref(i__, k);
  /* L270: */
  			}
  		    }
  		    i__1 = k - 1;
  		    for (j = 1; j <= i__1; ++j) {
  			if (a_ref(j, k) != 0.) {
  			    temp = a_ref(j, k);
  			    i__2 = *m;
  			    for (i__ = 1; i__ <= i__2; ++i__) {
  				b_ref(i__, j) = b_ref(i__, j) - temp * b_ref(
  					i__, k);
  /* L280: */
  			    }
  			}
  /* L290: */
  		    }
  		    if (*alpha != 1.) {
  			i__1 = *m;
  			for (i__ = 1; i__ <= i__1; ++i__) {
  			    b_ref(i__, k) = *alpha * b_ref(i__, k);
  /* L300: */
  			}
  		    }
  /* L310: */
  		}
  	    } else {
  		i__1 = *n;
  		for (k = 1; k <= i__1; ++k) {
  		    if (nounit) {
  			temp = 1. / a_ref(k, k);
  			i__2 = *m;
  			for (i__ = 1; i__ <= i__2; ++i__) {
  			    b_ref(i__, k) = temp * b_ref(i__, k);
  /* L320: */
  			}
  		    }
  		    i__2 = *n;
  		    for (j = k + 1; j <= i__2; ++j) {
  			if (a_ref(j, k) != 0.) {
  			    temp = a_ref(j, k);
  			    i__3 = *m;
  			    for (i__ = 1; i__ <= i__3; ++i__) {
  				b_ref(i__, j) = b_ref(i__, j) - temp * b_ref(
  					i__, k);
  /* L330: */
  			    }
  			}
  /* L340: */
  		    }
  		    if (*alpha != 1.) {
  			i__2 = *m;
  			for (i__ = 1; i__ <= i__2; ++i__) {
  			    b_ref(i__, k) = *alpha * b_ref(i__, k);
  /* L350: */
  			}
  		    }
  /* L360: */
  		}
  	    }
  	}
      }
      return 0;
  /*     End of DTRSM . */
  } /* dtrsm_ */
  #undef b_ref
  #undef a_ref
  
  