| 1 | ### deg =====================================================================
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| 2 |
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| 3 | Tags
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| 4 | ----
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| 5 | scripting, JS, internal, treenode, general concept
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| 6 |
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| 7 | Parameters
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| 8 | ----------
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| 9 | p,x
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| 10 |
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| 11 | General description
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| 12 | -------------------
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| 13 | Returns the degree of polynomial p(x).
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| 14 |
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| 15 | ###
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| 16 |
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| 17 |
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| 18 | Eval_degree = ->
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| 19 | push(cadr(p1))
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| 20 | Eval()
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| 21 | push(caddr(p1))
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| 22 | Eval()
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| 23 | p1 = pop()
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| 24 | if (p1 == symbol(NIL))
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| 25 | guess()
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| 26 | else
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| 27 | push(p1)
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| 28 | degree()
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| 29 |
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| 30 | #-----------------------------------------------------------------------------
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| 31 | #
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| 32 | # Find the degree of a polynomial
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| 33 | #
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| 34 | # Input: tos-2 p(x)
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| 35 | #
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| 36 | # tos-1 x
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| 37 | #
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| 38 | # Output: Result on stack
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| 39 | #
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| 40 | # Note: Finds the largest numerical power of x. Does not check for
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| 41 | # weirdness in p(x).
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| 42 | #
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| 43 | #-----------------------------------------------------------------------------
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| 44 |
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| 45 | #define POLY p1
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| 46 | #define X p2
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| 47 | #define DEGREE p3
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| 48 |
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| 49 | degree = ->
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| 50 | save()
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| 51 | p2 = pop()
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| 52 | p1 = pop()
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| 53 | p3 = zero
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| 54 | yydegree(p1)
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| 55 | push(p3)
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| 56 | restore()
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| 57 |
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| 58 | yydegree = (p) ->
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| 59 | if (equal(p, p2))
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| 60 | if (iszero(p3))
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| 61 | p3 = one
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| 62 | else if (car(p) == symbol(POWER))
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| 63 | if (equal(cadr(p), p2) && isnum(caddr(p)) && lessp(p3, caddr(p)))
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| 64 | p3 = caddr(p)
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| 65 | else if (iscons(p))
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| 66 | p = cdr(p)
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| 67 | while (iscons(p))
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| 68 | yydegree(car(p))
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| 69 | p = cdr(p)
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