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Diffstat (limited to 'lib/pure/numeric.nim')
-rw-r--r-- | lib/pure/numeric.nim | 87 |
1 files changed, 0 insertions, 87 deletions
diff --git a/lib/pure/numeric.nim b/lib/pure/numeric.nim deleted file mode 100644 index ccda3a146..000000000 --- a/lib/pure/numeric.nim +++ /dev/null @@ -1,87 +0,0 @@ -# -# -# Nim's Runtime Library -# (c) Copyright 2013 Robert Persson -# -# See the file "copying.txt", included in this -# distribution, for details about the copyright. -# - -## **Warning:** This module will be moved out of the stdlib and into a -## Nimble package, don't use it. - -type OneVarFunction* = proc (x: float): float - -{.deprecated: [TOneVarFunction: OneVarFunction].} - -proc brent*(xmin,xmax:float, function:OneVarFunction, tol:float,maxiter=1000): - tuple[rootx, rooty: float, success: bool]= - ## Searches `function` for a root between `xmin` and `xmax` - ## using brents method. If the function value at `xmin`and `xmax` has the - ## same sign, `rootx`/`rooty` is set too the extrema value closest to x-axis - ## and succes is set to false. - ## Otherwise there exists at least one root and success is set to true. - ## This root is searched for at most `maxiter` iterations. - ## If `tol` tolerance is reached within `maxiter` iterations - ## the root refinement stops and success=true. - - # see http://en.wikipedia.org/wiki/Brent%27s_method - var - a=xmin - b=xmax - c=a - d=1.0e308 - fa=function(a) - fb=function(b) - fc=fa - s=0.0 - fs=0.0 - mflag:bool - i=0 - tmp2:float - - if fa*fb>=0: - if abs(fa)<abs(fb): - return (a,fa,false) - else: - return (b,fb,false) - - if abs(fa)<abs(fb): - swap(fa,fb) - swap(a,b) - - while fb!=0.0 and abs(a-b)>tol: - if fa!=fc and fb!=fc: # inverse quadratic interpolation - s = a * fb * fc / (fa - fb) / (fa - fc) + b * fa * fc / (fb - fa) / (fb - fc) + c * fa * fb / (fc - fa) / (fc - fb) - else: #secant rule - s = b - fb * (b - a) / (fb - fa) - tmp2 = (3.0 * a + b) / 4.0 - if not((s > tmp2 and s < b) or (s < tmp2 and s > b)) or - (mflag and abs(s - b) >= (abs(b - c) / 2.0)) or - (not mflag and abs(s - b) >= abs(c - d) / 2.0): - s=(a+b)/2.0 - mflag=true - else: - if (mflag and (abs(b - c) < tol)) or (not mflag and (abs(c - d) < tol)): - s=(a+b)/2.0 - mflag=true - else: - mflag=false - fs = function(s) - d = c - c = b - fc = fb - if fa * fs<0.0: - b=s - fb=fs - else: - a=s - fa=fs - if abs(fa)<abs(fb): - swap(a,b) - swap(fa,fb) - inc i - if i>maxiter: - break - - return (b,fb,true) |