| 1 | #-----------------------------------------------------------------------------
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| 2 | #
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| 3 | # Author : philippe.billet@noos.fr
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| 4 | #
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| 5 | # Dirac function dirac(x)
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| 6 | # dirac(-x)=dirac(x)
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| 7 | # dirac(b-a)=dirac(a-b)
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| 8 | #-----------------------------------------------------------------------------
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| 9 |
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| 10 |
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| 11 |
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| 12 | Eval_dirac = ->
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| 13 | push(cadr(p1))
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| 14 | Eval()
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| 15 | dirac()
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| 16 |
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| 17 | dirac = ->
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| 18 | save()
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| 19 | ydirac()
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| 20 | restore()
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| 21 |
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| 22 | #define p1 p1
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| 23 |
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| 24 | ydirac = ->
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| 25 |
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| 26 | p1 = pop()
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| 27 |
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| 28 |
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| 29 |
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| 30 | if (isdouble(p1))
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| 31 | if (p1.d == 0)
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| 32 | push_integer(1)
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| 33 | return
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| 34 | else
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| 35 | push_integer(0)
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| 36 | return
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| 37 |
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| 38 | if (isrational(p1))
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| 39 | if (MZERO(mmul(p1.q.a,p1.q.b)))
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| 40 | push_integer(1)
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| 41 | return
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| 42 | else
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| 43 | push_integer(0)
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| 44 | return
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| 45 |
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| 46 |
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| 47 | if (car(p1) == symbol(POWER))
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| 48 | push_symbol(DIRAC)
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| 49 | push(cadr(p1))
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| 50 | list(2)
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| 51 | return
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| 52 |
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| 53 | if (isnegativeterm(p1))
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| 54 | push_symbol(DIRAC)
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| 55 | push(p1)
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| 56 | negate()
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| 57 | list(2)
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| 58 | return
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| 59 |
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| 60 | if (isnegativeterm(p1) || (car(p1) == symbol(ADD) && isnegativeterm(cadr(p1))))
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| 61 | push(p1)
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| 62 | negate()
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| 63 | p1 = pop()
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| 64 |
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| 65 |
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| 66 | push_symbol(DIRAC)
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| 67 | push(p1)
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| 68 | list(2)
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| 69 |
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