2528df0f75
These changes make it unnecessary to copy header files around during the build process, which tends to confuse IDEs and debuggers. The headers which comprise Cantera's external C++ interface are now in the 'include' directory. All of the samples and demos are now in the 'samples' subdirectory.
64 lines
1.7 KiB
Python
Executable file
64 lines
1.7 KiB
Python
Executable file
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def interp(z0, z, f):
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"""
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Linear interpolation.
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Sequences z and f must be of the same length,
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and the entries in z must be monotonically increasing.
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Example:
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>>> z = [0.0, 0.2, 0.5, 1.2, 2.1]
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>>> f = [3.0, 2.0, 1.0, 0.0, -1.0]
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>>>print interp(-2, z, f), interp(0.5, z, f), interp(6, z, f)
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3.0 7.0 -9.0
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"""
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n = len(z)
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# if z0 is outside the range of z, then return the endpoint value,
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# instead of extrapolating.
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if z0 <= z[0]:
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return f[0]
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elif z0 > z[-1]:
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return f[-1]
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for i in range(1,n):
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if z0 <= z[i]:
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return f[i-1] + (f[i] - f[i-1])*(z0 - z[i-1])/(z[i] - z[i-1])
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# if this statement is reached, then there is an error.
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raise 'interpolation error!'
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def quadInterp(z0, z, f):
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n = len(z)
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# if z0 is outside the range of z, then return the endpoint value,
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# instead of extrapolating.
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if z0 <= z[0]:
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return f[0]
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elif z0 > z[-1]:
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return f[-1]
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for i in range(1,n):
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if z0 <= z[i]:
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j = max(2,i)
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dx21 = z[j-1] - z[j-2]
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dx32 = z[j] - z[j-1]
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dx31 = dx21 + dx32
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dy32 = f[j] - f[j-1]
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dy21 = f[j-1] - f[j-2]
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a = (dx21*dy32 - dy21*dx32)/(dx21*dx31*dx32)
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return a*(z0 - z[j-2])*(z0 - z[j-1]) + (
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(dy21/dx21)*(z0 - z[j-1]) + f[j-1])
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# if this statement is reached, then there is an error.
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raise 'interpolation error!'
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## if __name__ == '__main__':
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## z = [0.0, 0.2, 0.5, 1.2, 2.1]
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## f = [3.0, 5.0, 11.0, 0.0, -9.0]
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## print interp(-2, z, f), interp(0.3, z, f), interp(6, z, f)
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## print quadInterp(-2, z, f), quadInterp(0.3, z, f), quadInterp(6, z, f)
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