#include "blaswrap.h" /* -- translated by f2c (version 19990503). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" /* Common Block Declarations */ struct { integer iparms[100]; } claenv_; #define claenv_1 claenv_ /* Table of constant values */ static integer c__0 = 0; static real c_b3 = 0.f; static real c_b4 = 1.f; static integer c__1 = 1; integer ilaenv_(integer *ispec, char *name__, char *opts, integer *n1, integer *n2, integer *n3, integer *n4, ftnlen name_len, ftnlen opts_len) { /* System generated locals */ integer ret_val; /* Local variables */ extern integer ieeeck_(integer *, real *, real *); /* -- LAPACK auxiliary routine (version 3.0) -- Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., Courant Institute, Argonne National Lab, and Rice University June 30, 1999 Purpose ======= ILAENV returns problem-dependent parameters for the local environment. See ISPEC for a description of the parameters. In this version, the problem-dependent parameters are contained in the integer array IPARMS in the common block CLAENV and the value with index ISPEC is copied to ILAENV. This version of ILAENV is to be used in conjunction with XLAENV in TESTING and TIMING. Arguments ========= ISPEC (input) INTEGER Specifies the parameter to be returned as the value of ILAENV. = 1: the optimal blocksize; if this value is 1, an unblocked algorithm will give the best performance. = 2: the minimum block size for which the block routine should be used; if the usable block size is less than this value, an unblocked routine should be used. = 3: the crossover point (in a block routine, for N less than this value, an unblocked routine should be used) = 4: the number of shifts, used in the nonsymmetric eigenvalue routines = 5: the minimum column dimension for blocking to be used; rectangular blocks must have dimension at least k by m, where k is given by ILAENV(2,...) and m by ILAENV(5,...) = 6: the crossover point for the SVD (when reducing an m by n matrix to bidiagonal form, if max(m,n)/min(m,n) exceeds this value, a QR factorization is used first to reduce the matrix to a triangular form.) = 7: the number of processors = 8: the crossover point for the multishift QR and QZ methods for nonsymmetric eigenvalue problems. = 9: maximum size of the subproblems at the bottom of the computation tree in the divide-and-conquer algorithm =10: ieee NaN arithmetic can be trusted not to trap =11: infinity arithmetic can be trusted not to trap Other specifications (up to 100) can be added later. NAME (input) CHARACTER*(*) The name of the calling subroutine. OPTS (input) CHARACTER*(*) The character options to the subroutine NAME, concatenated into a single character string. For example, UPLO = 'U', TRANS = 'T', and DIAG = 'N' for a triangular routine would be specified as OPTS = 'UTN'. N1 (input) INTEGER N2 (input) INTEGER N3 (input) INTEGER N4 (input) INTEGER Problem dimensions for the subroutine NAME; these may not all be required. (ILAENV) (output) INTEGER >= 0: the value of the parameter specified by ISPEC < 0: if ILAENV = -k, the k-th argument had an illegal value. Further Details =============== The following conventions have been used when calling ILAENV from the LAPACK routines: 1) OPTS is a concatenation of all of the character options to subroutine NAME, in the same order that they appear in the argument list for NAME, even if they are not used in determining the value of the parameter specified by ISPEC. 2) The problem dimensions N1, N2, N3, N4 are specified in the order that they appear in the argument list for NAME. N1 is used first, N2 second, and so on, and unused problem dimensions are passed a value of -1. 3) The parameter value returned by ILAENV is checked for validity in the calling subroutine. For example, ILAENV is used to retrieve the optimal blocksize for STRTRI as follows: NB = ILAENV( 1, 'STRTRI', UPLO // DIAG, N, -1, -1, -1 ) IF( NB.LE.1 ) NB = MAX( 1, N ) ===================================================================== */ if (*ispec >= 1 && *ispec <= 5) { /* Return a value from the common block. */ ret_val = claenv_1.iparms[*ispec - 1]; } else if (*ispec == 6) { /* Compute SVD crossover point. */ ret_val = (integer) ((real) min(*n1,*n2) * 1.6f); } else if (*ispec >= 7 && *ispec <= 9) { /* Return a value from the common block. */ ret_val = claenv_1.iparms[*ispec - 1]; } else if (*ispec == 10) { /* IEEE NaN arithmetic can be trusted not to trap */ ret_val = 1; if (ret_val == 1) { ret_val = ieeeck_(&c__0, &c_b3, &c_b4); } } else if (*ispec == 11) { /* Infinity arithmetic can be trusted not to trap */ ret_val = 1; if (ret_val == 1) { ret_val = ieeeck_(&c__1, &c_b3, &c_b4); } } else { /* Invalid value for ISPEC */ ret_val = -1; } return ret_val; /* End of ILAENV */ } /* ilaenv_ */