Fix workspace query corner case

angsch · angsch · commit 98f3f675f90a · 2023-07-11T15:56:42.000+02:00
If N = 0, a workspace query returns WORK( 1 ) = 0 as the required
workspace. If this result is used to allocate workspace, then
LWORK = 0 and the next call triggers xerbla since LWORK.LT.1.
diff --git a/SRC/csytrf.f b/SRC/csytrf.f
@@ -232,7 +232,7 @@ SUBROUTINE CSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )
 *        Determine the block size
 *
          NB = ILAENV( 1, 'CSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/csytrf_rk.f b/SRC/csytrf_rk.f
@@ -310,7 +310,7 @@ SUBROUTINE CSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,
 *        Determine the block size
 *
          NB = ILAENV( 1, 'CSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/ctrevc3.f b/SRC/ctrevc3.f
@@ -321,9 +321,9 @@ SUBROUTINE CTREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
 *
       INFO = 0
       NB = ILAENV( 1, 'CTREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
-      RWORK(1) = N
+      RWORK(1) = MAX( 1, N )
       LQUERY = ( LWORK.EQ.-1 .OR. LRWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN
          INFO = -1
diff --git a/SRC/dsytrf.f b/SRC/dsytrf.f
@@ -232,7 +232,7 @@ SUBROUTINE DSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )
 *        Determine the block size
 *
          NB = ILAENV( 1, 'DSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/dsytrf_rk.f b/SRC/dsytrf_rk.f
@@ -310,7 +310,7 @@ SUBROUTINE DSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,
 *        Determine the block size
 *
          NB = ILAENV( 1, 'DSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/dtrevc3.f b/SRC/dtrevc3.f
@@ -298,7 +298,7 @@ SUBROUTINE DTREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,
 *
       INFO = 0
       NB = ILAENV( 1, 'DTREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
       LQUERY = ( LWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN
diff --git a/SRC/ssytrf.f b/SRC/ssytrf.f
@@ -232,7 +232,7 @@ SUBROUTINE SSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )
 *        Determine the block size
 *
          NB = ILAENV( 1, 'SSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/ssytrf_rk.f b/SRC/ssytrf_rk.f
@@ -310,7 +310,7 @@ SUBROUTINE SSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,
 *        Determine the block size
 *
          NB = ILAENV( 1, 'SSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/strevc3.f b/SRC/strevc3.f
@@ -298,7 +298,7 @@ SUBROUTINE STREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,
 *
       INFO = 0
       NB = ILAENV( 1, 'STREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
       LQUERY = ( LWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN
diff --git a/SRC/zsytrf.f b/SRC/zsytrf.f
@@ -232,7 +232,7 @@ SUBROUTINE ZSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )
 *        Determine the block size
 *
          NB = ILAENV( 1, 'ZSYTRF', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/zsytrf_rk.f b/SRC/zsytrf_rk.f
@@ -310,7 +310,7 @@ SUBROUTINE ZSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,
 *        Determine the block size
 *
          NB = ILAENV( 1, 'ZSYTRF_RK', UPLO, N, -1, -1, -1 )
-         LWKOPT = N*NB
+         LWKOPT = MAX( 1, N*NB )
          WORK( 1 ) = LWKOPT
       END IF
 *
diff --git a/SRC/ztrevc3.f b/SRC/ztrevc3.f
@@ -321,9 +321,9 @@ SUBROUTINE ZTREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
 *
       INFO = 0
       NB = ILAENV( 1, 'ZTREVC', SIDE // HOWMNY, N, -1, -1, -1 )
-      MAXWRK = N + 2*N*NB
+      MAXWRK = MAX( 1, N + 2*N*NB )
       WORK(1) = MAXWRK
-      RWORK(1) = N
+      RWORK(1) = MAX( 1, N )
       LQUERY = ( LWORK.EQ.-1 .OR. LRWORK.EQ.-1 )
       IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN
          INFO = -1

Original file line number	Diff line number	Diff line change
`@@ -232,7 +232,7 @@ SUBROUTINE CSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )`
`232`	`232`	`* Determine the block size`
`233`	`233`	`*`
`234`	`234`	`NB = ILAENV( 1, 'CSYTRF', UPLO, N, -1, -1, -1 )`
`235`		`- LWKOPT = N*NB`
	`235`	`+ LWKOPT = MAX( 1, N*NB )`
`236`	`236`	`WORK( 1 ) = LWKOPT`
`237`	`237`	`END IF`
`238`	`238`	`*`
Original file line number	Diff line number	Diff line change
`@@ -310,7 +310,7 @@ SUBROUTINE CSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,`
`310`	`310`	`* Determine the block size`
`311`	`311`	`*`
`312`	`312`	`NB = ILAENV( 1, 'CSYTRF_RK', UPLO, N, -1, -1, -1 )`
`313`		`- LWKOPT = N*NB`
	`313`	`+ LWKOPT = MAX( 1, N*NB )`
`314`	`314`	`WORK( 1 ) = LWKOPT`
`315`	`315`	`END IF`
`316`	`316`	`*`
Original file line number	Diff line number	Diff line change
`@@ -232,7 +232,7 @@ SUBROUTINE DSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )`
`232`	`232`	`* Determine the block size`
`233`	`233`	`*`
`234`	`234`	`NB = ILAENV( 1, 'DSYTRF', UPLO, N, -1, -1, -1 )`
`235`		`- LWKOPT = N*NB`
	`235`	`+ LWKOPT = MAX( 1, N*NB )`
`236`	`236`	`WORK( 1 ) = LWKOPT`
`237`	`237`	`END IF`
`238`	`238`	`*`
Original file line number	Diff line number	Diff line change
`@@ -310,7 +310,7 @@ SUBROUTINE DSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,`
`310`	`310`	`* Determine the block size`
`311`	`311`	`*`
`312`	`312`	`NB = ILAENV( 1, 'DSYTRF_RK', UPLO, N, -1, -1, -1 )`
`313`		`- LWKOPT = N*NB`
	`313`	`+ LWKOPT = MAX( 1, N*NB )`
`314`	`314`	`WORK( 1 ) = LWKOPT`
`315`	`315`	`END IF`
`316`	`316`	`*`
Original file line number	Diff line number	Diff line change
`@@ -298,7 +298,7 @@ SUBROUTINE DTREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,`
`298`	`298`	`*`
`299`	`299`	`INFO = 0`
`300`	`300`	`NB = ILAENV( 1, 'DTREVC', SIDE // HOWMNY, N, -1, -1, -1 )`
`301`		`- MAXWRK = N + 2NNB`
	`301`	`+ MAXWRK = MAX( 1, N + 2NNB )`
`302`	`302`	`WORK(1) = MAXWRK`
`303`	`303`	`LQUERY = ( LWORK.EQ.-1 )`
`304`	`304`	`IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN`
Original file line number	Diff line number	Diff line change
`@@ -232,7 +232,7 @@ SUBROUTINE SSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )`
`232`	`232`	`* Determine the block size`
`233`	`233`	`*`
`234`	`234`	`NB = ILAENV( 1, 'SSYTRF', UPLO, N, -1, -1, -1 )`
`235`		`- LWKOPT = N*NB`
	`235`	`+ LWKOPT = MAX( 1, N*NB )`
`236`	`236`	`WORK( 1 ) = LWKOPT`
`237`	`237`	`END IF`
`238`	`238`	`*`
Original file line number	Diff line number	Diff line change
`@@ -310,7 +310,7 @@ SUBROUTINE SSYTRF_RK( UPLO, N, A, LDA, E, IPIV, WORK, LWORK,`
`310`	`310`	`* Determine the block size`
`311`	`311`	`*`
`312`	`312`	`NB = ILAENV( 1, 'SSYTRF_RK', UPLO, N, -1, -1, -1 )`
`313`		`- LWKOPT = N*NB`
	`313`	`+ LWKOPT = MAX( 1, N*NB )`
`314`	`314`	`WORK( 1 ) = LWKOPT`
`315`	`315`	`END IF`
`316`	`316`	`*`
Original file line number	Diff line number	Diff line change
`@@ -298,7 +298,7 @@ SUBROUTINE STREVC3( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL,`
`298`	`298`	`*`
`299`	`299`	`INFO = 0`
`300`	`300`	`NB = ILAENV( 1, 'STREVC', SIDE // HOWMNY, N, -1, -1, -1 )`
`301`		`- MAXWRK = N + 2NNB`
	`301`	`+ MAXWRK = MAX( 1, N + 2NNB )`
`302`	`302`	`WORK(1) = MAXWRK`
`303`	`303`	`LQUERY = ( LWORK.EQ.-1 )`
`304`	`304`	`IF( .NOT.RIGHTV .AND. .NOT.LEFTV ) THEN`
Original file line number	Diff line number	Diff line change
`@@ -232,7 +232,7 @@ SUBROUTINE ZSYTRF( UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO )`
`232`	`232`	`* Determine the block size`
`233`	`233`	`*`
`234`	`234`	`NB = ILAENV( 1, 'ZSYTRF', UPLO, N, -1, -1, -1 )`
`235`		`- LWKOPT = N*NB`
	`235`	`+ LWKOPT = MAX( 1, N*NB )`
`236`	`236`	`WORK( 1 ) = LWKOPT`
`237`	`237`	`END IF`
`238`	`238`	`*`