LAPACK 3.12.1
LAPACK: Linear Algebra PACKage
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◆ ieeeck()

integer function ieeeck ( integer ispec,
real zero,
real one )

IEEECK

Download IEEECK + dependencies [TGZ] [ZIP] [TXT]

Purpose:
!>
!> IEEECK is called from the ILAENV to verify that Infinity and
!> possibly NaN arithmetic is safe (i.e. will not trap).
!>
Parameters
[in]ISPEC
!>          ISPEC is INTEGER
!>          Specifies whether to test just for infinity arithmetic
!>          or whether to test for infinity and NaN arithmetic.
!>          = 0: Verify infinity arithmetic only.
!>          = 1: Verify infinity and NaN arithmetic.
!>
[in]ZERO
!>          ZERO is REAL
!>          Must contain the value 0.0
!>          This is passed to prevent the compiler from optimizing
!>          away this code.
!>
[in]ONE
!>          ONE is REAL
!>          Must contain the value 1.0
!>          This is passed to prevent the compiler from optimizing
!>          away this code.
!>
!>  RETURN VALUE:  INTEGER
!>          = 0:  Arithmetic failed to produce the correct answers
!>          = 1:  Arithmetic produced the correct answers
!>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.

Definition at line 79 of file ieeeck.f.

80*
81* -- LAPACK auxiliary routine --
82* -- LAPACK is a software package provided by Univ. of Tennessee, --
83* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
84*
85* .. Scalar Arguments ..
86 INTEGER ISPEC
87 REAL ONE, ZERO
88* ..
89*
90* =====================================================================
91*
92* .. Local Scalars ..
93 REAL NAN1, NAN2, NAN3, NAN4, NAN5, NAN6, NEGINF,
94 $ NEGZRO, NEWZRO, POSINF
95* ..
96* .. Executable Statements ..
97 ieeeck = 1
98*
99 posinf = one / zero
100 IF( posinf.LE.one ) THEN
101 ieeeck = 0
102 RETURN
103 END IF
104*
105 neginf = -one / zero
106 IF( neginf.GE.zero ) THEN
107 ieeeck = 0
108 RETURN
109 END IF
110*
111 negzro = one / ( neginf+one )
112 IF( negzro.NE.zero ) THEN
113 ieeeck = 0
114 RETURN
115 END IF
116*
117 neginf = one / negzro
118 IF( neginf.GE.zero ) THEN
119 ieeeck = 0
120 RETURN
121 END IF
122*
123 newzro = negzro + zero
124 IF( newzro.NE.zero ) THEN
125 ieeeck = 0
126 RETURN
127 END IF
128*
129 posinf = one / newzro
130 IF( posinf.LE.one ) THEN
131 ieeeck = 0
132 RETURN
133 END IF
134*
135 neginf = neginf*posinf
136 IF( neginf.GE.zero ) THEN
137 ieeeck = 0
138 RETURN
139 END IF
140*
141 posinf = posinf*posinf
142 IF( posinf.LE.one ) THEN
143 ieeeck = 0
144 RETURN
145 END IF
146*
147*
148*
149*
150* Return if we were only asked to check infinity arithmetic
151*
152 IF( ispec.EQ.0 )
153 $ RETURN
154*
155 nan1 = posinf + neginf
156*
157 nan2 = posinf / neginf
158*
159 nan3 = posinf / posinf
160*
161 nan4 = posinf*zero
162*
163 nan5 = neginf*negzro
164*
165 nan6 = nan5*zero
166*
167 IF( nan1.EQ.nan1 ) THEN
168 ieeeck = 0
169 RETURN
170 END IF
171*
172 IF( nan2.EQ.nan2 ) THEN
173 ieeeck = 0
174 RETURN
175 END IF
176*
177 IF( nan3.EQ.nan3 ) THEN
178 ieeeck = 0
179 RETURN
180 END IF
181*
182 IF( nan4.EQ.nan4 ) THEN
183 ieeeck = 0
184 RETURN
185 END IF
186*
187 IF( nan5.EQ.nan5 ) THEN
188 ieeeck = 0
189 RETURN
190 END IF
191*
192 IF( nan6.EQ.nan6 ) THEN
193 ieeeck = 0
194 RETURN
195 END IF
196*
197 RETURN
ieeeck
integer function ieeeck(ispec, zero, one)
IEEECK
Definition ieeeck.f:80
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