GCC Code Coverage Report

Directory:	./
File:	misc/pchdf.f
Date:	2022-01-11 19:19:34

	Exec	Total	Coverage
Lines:	0	17	0.0%
Branches:	0	8	0.0%

Line	Exec	Source
1		*DECK PCHDF
2	✗	REAL FUNCTION PCHDF (K, X, S, IERR)
3		C***BEGIN PROLOGUE PCHDF
4		C***SUBSIDIARY
5		C***PURPOSE Computes divided differences for PCHCE and PCHSP
6		C***LIBRARY SLATEC (PCHIP)
7		C***TYPE SINGLE PRECISION (PCHDF-S, DPCHDF-D)
8		C***AUTHOR Fritsch, F. N., (LLNL)
9		C***DESCRIPTION
10		C
11		C PCHDF: PCHIP Finite Difference Formula
12		C
13		C Uses a divided difference formulation to compute a K-point approx-
14		C imation to the derivative at X(K) based on the data in X and S.
15		C
16		C Called by PCHCE and PCHSP to compute 3- and 4-point boundary
17		C derivative approximations.
18		C
19		C ----------------------------------------------------------------------
20		C
21		C On input:
22		C K is the order of the desired derivative approximation.
23		C K must be at least 3 (error return if not).
24		C X contains the K values of the independent variable.
25		C X need not be ordered, but the values MUST be
26		C distinct. (Not checked here.)
27		C S contains the associated slope values:
28		C S(I) = (F(I+1)-F(I))/(X(I+1)-X(I)), I=1(1)K-1.
29		C (Note that S need only be of length K-1.)
30		C
31		C On return:
32		C S will be destroyed.
33		C IERR will be set to -1 if K.LT.2 .
34		C PCHDF will be set to the desired derivative approximation if
35		C IERR=0 or to zero if IERR=-1.
36		C
37		C ----------------------------------------------------------------------
38		C
39		C***SEE ALSO PCHCE, PCHSP
40		C***REFERENCES Carl de Boor, A Practical Guide to Splines, Springer-
41		C Verlag, New York, 1978, pp. 10-16.
42		C***ROUTINES CALLED XERMSG
43		C***REVISION HISTORY (YYMMDD)
44		C 820503 DATE WRITTEN
45		C 820805 Converted to SLATEC library version.
46		C 870813 Minor cosmetic changes.
47		C 890411 Added SAVE statements (Vers. 3.2).
48		C 890411 REVISION DATE from Version 3.2
49		C 891214 Prologue converted to Version 4.0 format. (BAB)
50		C 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
51		C 900328 Added TYPE section. (WRB)
52		C 910408 Updated AUTHOR and DATE WRITTEN sections in prologue. (WRB)
53		C 920429 Revised format and order of references. (WRB,FNF)
54		C 930503 Improved purpose. (FNF)
55		C***END PROLOGUE PCHDF
56		C
57		C**End
58		C
59		C DECLARE ARGUMENTS.
60		C
61		INTEGER K, IERR
62		REAL X(K), S(K)
63		C
64		C DECLARE LOCAL VARIABLES.
65		C
66		INTEGER I, J
67		REAL VALUE, ZERO
68		SAVE ZERO
69		DATA ZERO /0./
70		C
71		C CHECK FOR LEGAL VALUE OF K.
72		C
73		C***FIRST EXECUTABLE STATEMENT PCHDF
74	✗	IF (K .LT. 3) GO TO 5001
75		C
76		C COMPUTE COEFFICIENTS OF INTERPOLATING POLYNOMIAL.
77		C
78	✗	DO 10 J = 2, K-1
79	✗	DO 9 I = 1, K-J
80	✗	S(I) = (S(I+1)-S(I))/(X(I+J)-X(I))
81	✗	9 CONTINUE
82	✗	10 CONTINUE
83		C
84		C EVALUATE DERIVATIVE AT X(K).
85		C
86	✗	VALUE = S(1)
87	✗	DO 20 I = 2, K-1
88	✗	VALUE = S(I) + VALUE*(X(K)-X(I))
89	✗	20 CONTINUE
90		C
91		C NORMAL RETURN.
92		C
93	✗	IERR = 0
94		PCHDF = VALUE
95	✗	RETURN
96		C
97		C ERROR RETURN.
98		C
99		5001 CONTINUE
100		C K.LT.3 RETURN.
101	✗	IERR = -1
102	✗	CALL XERMSG ('SLATEC', 'PCHDF', 'K LESS THAN THREE', IERR, 1)
103	✗	PCHDF = ZERO
104	✗	RETURN
105		C------------- LAST LINE OF PCHDF FOLLOWS ------------------------------
106		END
107

1

*DECK PCHDF

2

✗

REAL FUNCTION PCHDF (K, X, S, IERR)

3

C***BEGIN PROLOGUE PCHDF

4

C***SUBSIDIARY

5

C***PURPOSE Computes divided differences for PCHCE and PCHSP

6

C***LIBRARY SLATEC (PCHIP)

7

C***TYPE SINGLE PRECISION (PCHDF-S, DPCHDF-D)

8

C***AUTHOR Fritsch, F. N., (LLNL)

9

C***DESCRIPTION

10

C

11

C PCHDF: PCHIP Finite Difference Formula

12

C

13

C Uses a divided difference formulation to compute a K-point approx-

14

C imation to the derivative at X(K) based on the data in X and S.

15

C

16

C Called by PCHCE and PCHSP to compute 3- and 4-point boundary

17

C derivative approximations.

18

C

19

C ----------------------------------------------------------------------

20

C

21

C On input:

22

C K is the order of the desired derivative approximation.

23

C K must be at least 3 (error return if not).

24

C X contains the K values of the independent variable.

25

C X need not be ordered, but the values **MUST** be

26

C distinct. (Not checked here.)

27

C S contains the associated slope values:

28

C S(I) = (F(I+1)-F(I))/(X(I+1)-X(I)), I=1(1)K-1.

29

C (Note that S need only be of length K-1.)

30

C

31

C On return:

32

C S will be destroyed.

33

C IERR will be set to -1 if K.LT.2 .

34

C PCHDF will be set to the desired derivative approximation if

35

C IERR=0 or to zero if IERR=-1.

36

C

37

C ----------------------------------------------------------------------

38

C

39

C***SEE ALSO PCHCE, PCHSP

40

C***REFERENCES Carl de Boor, A Practical Guide to Splines, Springer-

41

C Verlag, New York, 1978, pp. 10-16.

42

C***ROUTINES CALLED XERMSG

43

C***REVISION HISTORY (YYMMDD)

44

C 820503 DATE WRITTEN

45

C 820805 Converted to SLATEC library version.

46

C 870813 Minor cosmetic changes.

47

C 890411 Added SAVE statements (Vers. 3.2).

48

C 890411 REVISION DATE from Version 3.2

49

C 891214 Prologue converted to Version 4.0 format. (BAB)

50

C 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)

51

C 900328 Added TYPE section. (WRB)

52

C 910408 Updated AUTHOR and DATE WRITTEN sections in prologue. (WRB)

53

C 920429 Revised format and order of references. (WRB,FNF)

54

C 930503 Improved purpose. (FNF)

55

C***END PROLOGUE PCHDF

C

C**End

C

C DECLARE ARGUMENTS.

C

INTEGER K, IERR

REAL X(K), S(K)

C

C DECLARE LOCAL VARIABLES.

C

INTEGER I, J

REAL VALUE, ZERO

SAVE ZERO

DATA ZERO /0./

C

C CHECK FOR LEGAL VALUE OF K.

72

C

73

C***FIRST EXECUTABLE STATEMENT PCHDF

74

✗

IF (K .LT. 3) GO TO 5001

75

C

76

C COMPUTE COEFFICIENTS OF INTERPOLATING POLYNOMIAL.

77

C

78

✗

DO 10 J = 2, K-1

79

✗

DO 9 I = 1, K-J

80

✗

S(I) = (S(I+1)-S(I))/(X(I+J)-X(I))

81

✗

9 CONTINUE

82

✗

10 CONTINUE

83

C

84

C EVALUATE DERIVATIVE AT X(K).

85

C

86

✗

VALUE = S(1)

87

✗

DO 20 I = 2, K-1

88

✗

VALUE = S(I) + VALUE*(X(K)-X(I))

89

✗

20 CONTINUE

C

C NORMAL RETURN.

C

✗

IERR = 0

94

PCHDF = VALUE

95

✗

RETURN

C

C ERROR RETURN.

C

5001 CONTINUE

C K.LT.3 RETURN.

✗

IERR = -1

102

✗

CALL XERMSG ('SLATEC', 'PCHDF', 'K LESS THAN THREE', IERR, 1)

103

✗

PCHDF = ZERO

104

✗

RETURN

105

C------------- LAST LINE OF PCHDF FOLLOWS ------------------------------

106

END

107