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---
:name: slasy2
:md5sum: ae3def82cfd379e2cd0add43bc32316d
:category: :subroutine
:arguments:
- ltranl:
:type: logical
:intent: input
- ltranr:
:type: logical
:intent: input
- isgn:
:type: integer
:intent: input
- n1:
:type: integer
:intent: input
- n2:
:type: integer
:intent: input
- tl:
:type: real
:intent: input
:dims:
- ldtl
- "2"
- ldtl:
:type: integer
:intent: input
- tr:
:type: real
:intent: input
:dims:
- ldtr
- "2"
- ldtr:
:type: integer
:intent: input
- b:
:type: real
:intent: input
:dims:
- ldb
- "2"
- ldb:
:type: integer
:intent: input
- scale:
:type: real
:intent: output
- x:
:type: real
:intent: output
:dims:
- ldx
- "2"
- ldx:
:type: integer
:intent: input
- xnorm:
:type: real
:intent: output
- info:
:type: integer
:intent: output
:substitutions:
ldx: MAX(1,n1)
:fortran_help: " SUBROUTINE SLASY2( LTRANL, LTRANR, ISGN, N1, N2, TL, LDTL, TR, LDTR, B, LDB, SCALE, X, LDX, XNORM, INFO )\n\n\
* Purpose\n\
* =======\n\
*\n\
* SLASY2 solves for the N1 by N2 matrix X, 1 <= N1,N2 <= 2, in\n\
*\n\
* op(TL)*X + ISGN*X*op(TR) = SCALE*B,\n\
*\n\
* where TL is N1 by N1, TR is N2 by N2, B is N1 by N2, and ISGN = 1 or\n\
* -1. op(T) = T or T', where T' denotes the transpose of T.\n\
*\n\n\
* Arguments\n\
* =========\n\
*\n\
* LTRANL (input) LOGICAL\n\
* On entry, LTRANL specifies the op(TL):\n\
* = .FALSE., op(TL) = TL,\n\
* = .TRUE., op(TL) = TL'.\n\
*\n\
* LTRANR (input) LOGICAL\n\
* On entry, LTRANR specifies the op(TR):\n\
* = .FALSE., op(TR) = TR,\n\
* = .TRUE., op(TR) = TR'.\n\
*\n\
* ISGN (input) INTEGER\n\
* On entry, ISGN specifies the sign of the equation\n\
* as described before. ISGN may only be 1 or -1.\n\
*\n\
* N1 (input) INTEGER\n\
* On entry, N1 specifies the order of matrix TL.\n\
* N1 may only be 0, 1 or 2.\n\
*\n\
* N2 (input) INTEGER\n\
* On entry, N2 specifies the order of matrix TR.\n\
* N2 may only be 0, 1 or 2.\n\
*\n\
* TL (input) REAL array, dimension (LDTL,2)\n\
* On entry, TL contains an N1 by N1 matrix.\n\
*\n\
* LDTL (input) INTEGER\n\
* The leading dimension of the matrix TL. LDTL >= max(1,N1).\n\
*\n\
* TR (input) REAL array, dimension (LDTR,2)\n\
* On entry, TR contains an N2 by N2 matrix.\n\
*\n\
* LDTR (input) INTEGER\n\
* The leading dimension of the matrix TR. LDTR >= max(1,N2).\n\
*\n\
* B (input) REAL array, dimension (LDB,2)\n\
* On entry, the N1 by N2 matrix B contains the right-hand\n\
* side of the equation.\n\
*\n\
* LDB (input) INTEGER\n\
* The leading dimension of the matrix B. LDB >= max(1,N1).\n\
*\n\
* SCALE (output) REAL\n\
* On exit, SCALE contains the scale factor. SCALE is chosen\n\
* less than or equal to 1 to prevent the solution overflowing.\n\
*\n\
* X (output) REAL array, dimension (LDX,2)\n\
* On exit, X contains the N1 by N2 solution.\n\
*\n\
* LDX (input) INTEGER\n\
* The leading dimension of the matrix X. LDX >= max(1,N1).\n\
*\n\
* XNORM (output) REAL\n\
* On exit, XNORM is the infinity-norm of the solution.\n\
*\n\
* INFO (output) INTEGER\n\
* On exit, INFO is set to\n\
* 0: successful exit.\n\
* 1: TL and TR have too close eigenvalues, so TL or\n\
* TR is perturbed to get a nonsingular equation.\n\
* NOTE: In the interests of speed, this routine does not\n\
* check the inputs for errors.\n\
*\n\n\
* =====================================================================\n\
*\n"
|
