FAQ Database Discussion Community


Matlab how define an integral function and find best coefficients

matlab,integral,best-fit-curve
I would like to find coefficients to best fit the nonlinear functions, and the nonlinear functions was an integral function. So the first step was to define an function: function dT = km(x,sT) fun=@(temp)((-x(1)*x(2)*(temp).^(x(2)-1.0))./ ... ((x(3)^x(2))*((1+(temp./x(3)).^x(2)).^2))); dT=integral(fun,0,sT); % x is a array containing three coefficients; % sT is a array...

Fit an integral function with parametric limit to data with Python (Debye Model)

python,python-2.7,python-2.x,integral,data-fitting
I am trying to fit resistivity vs temperature data to Bloch-Gruneisen formula for resistivity in metals: function as you can see there is an integral function with a parametric limit. I don't know how to implement an algorithm to run a least squares fit. I came up with: import matplotlib.pyplot...

Best way to integrate user defined function

matlab,integral
I would like to evaluate an expression which requires an integral of a user defined function. I have 3 inputs to the integral expression, E,F and B. F and B are values stored in separate arrays. E is the parameter I would like to integrate over, from a value of...

Double integral with variable boundaries in python Scipy + sympy (?)

python,scipy,sympy,integral
The full mathematical problem is here. Briefly I want to integrate a function with a double integral. The inner integral has boundaries 20 and x-2, while the outer has boundaries 22 and 30. I know that with Scipy I can compute the double integral with scipy.integrate.nquad. I would like to...

Does reinterpret_casting an integral to a pointer type and back yield the same value?

c++,pointers,language-lawyer,integral,reinterpret-cast
According to http://en.cppreference.com/w/cpp/language/reinterpret_cast, it is known that reinterpret_cast a pointer to an integral of sufficient size and back yield the same value. I'm wondering whether the converse is also true by the standards. That is, does reinterpret_cast an integral to a pointer type of sufficient size and back yield the...

C++: How to compute an integral with interval bounds?

c++,algorithm,integral,polynomials
I am both tired, new to C++ and real bad at dealing with polynomials. That's a bad combo for my assignment. Nevertheless I am trying to solve it. Please note that I might have misunderstood certain parts both mathematically and language-wise. Maybe even terminology. The first task of my assignment...

SymPy integration, constant term

python,python-2.x,sympy,integral
I can't understand behavior of sympy.integrate() function. The simplest example, integrate and differentiate: t = sy.Symbol('t') t1 = sy.Symbol('t1') f = sy.Function('f')(t) I = sy.integrate(f, (t, 0, t1)) f1 = I.diff(t1) print f1 prints the following: f(t1) + Integral(0, (t, 0, t1)) But I expect to see just f(t). Calling...

How do I print out Integeral values in haskell without warning using show?

haskell,warnings,show,ghci,integral
When I run the following haskell code with warnings enabled module Main where main :: IO() main = interact (unlines.strout.calc.extinps.words) --calculates factorial factorial :: Integral a=> a->a factorial n = product [1..n] --Extracts numbers from the input extinps ::(Read b)=>[String]->[b] extinps x=map read x --Calculates the factorial calc :: (Integral...

Trapezoidal Integration is not accurate enough in Clojure

clojure,integral
So currently, I wrote a Clojure code to do Trapezoidal integration of a polynomial function in HackerRank.com: https://www.hackerrank.com/challenges/area-under-curves-and-volume-of-revolving-a-curv (defn abs[x] (max x (- 0 x)) ) (defn exp[x n] (if (> n 0) (* x (exp x (- n 1))) 1 ) ) (defn fact[x] (if (> x 0) (*...

Integral of piecewise function gives incorrect result

python,sympy,integral
Using the recent version of sympy (0.7.6) I get the following bad result when determining the integral of a function with support [0,y): from sympy import * a,b,c,x,z = symbols("a,b,c,x,z",real = True) y = Symbol("y",real=True,positive=True) inner = Piecewise((0,(x>=y)|(x<0)|(b>c)),(a,True)) I = Integral(inner,(x,0,z)) Eq(I,I.doit()) This is incorrect as the actual result should...

Volume of a part of a sphere cutted using 3 planes using R-Language (integral)

r,volume,integral
I want to calculate the volume (V) of a part of sphere, which is the result of intersetion of the sphere with three palnes (x=0, y=0 and z=1.5). I am using R-Language and this is my code. I tried 2 different methods using cartesian and polar coordinates. Both of them...

Integrate histogram in python?

python,matplotlib,plot,integral
Is there a simple command in matplotlib that let's me take the integral of histogram over a certain range? If I plot a histogram with: fig = plt.hist(x, bins) Then, is there a command like fig.integral(bin1, bin2)? That will return the integral of the histogram from bin1 to bin2?

scipy.integrate.quad on arrays of limits

python,arrays,numpy,scipy,integral
quad from scipy.integrate needs the arguments func, a, b. Where func is a function to integrate and a and b is the lower and upper integration limits, respectively. a and b has to be numbers. I have a situation where I need to evaluate the integral of a function for...