MATLAB to Python Code Conversion: Implementing a For Loop with State Equations

This example demonstrates how to convert a MATLAB for loop into Python code. The loop involves calculations related to state equations using functions like 'wye_sumeq' and 'kimura_stateq'. This conversion is crucial when migrating MATLAB projects to Python.

Original MATLAB Code:

for j=t
    k=k+1;
    [WYf, WYe] = wye_sumeq(w_w, leg_num,  yf, ye);
    [uf_dot, vf_dot,ue_dot, ve_dot] = kimura_stateq(Tr, Ta, uf, vf, ue, ve, yf, ye,a, b, c,WYf, WYe, shsum);
    uf =uf + ts.*uf_dot;
    vf =vf + ts.*vf_dot;
    ue =ue + ts.*ue_dot;
    ve =ve + ts.*ve_dot;
    Y_Y = uf - ue;
    trace_Y_Y(:,k)= Y_Y ;
    [yf, ye] = returnyfe(uf, ue, leg_num);
end

Python Code:

for j in range(t):
    k = k + 1
    WYf, WYe = wye_sumeq(w_w, leg_num, yf, ye)
    uf_dot, vf_dot, ue_dot, ve_dot = kimura_stateq(Tr, Ta, uf, vf, ue, ve, yf, ye, a, b, c, WYf, WYe, shsum)
    uf = uf + ts * uf_dot
    vf = vf + ts * vf_dot
    ue = ue + ts * ue_dot
    ve = ve + ts * ve_dot
    Y_Y = uf - ue
    trace_Y_Y[:, k] = Y_Y
    yf, ye = returnyfe(uf, ue, leg_num)

This Python code effectively replicates the MATLAB for loop. Key points include:

• Range Function: range(t) is used to create an iterable sequence of numbers from 0 to t-1, mimicking MATLAB's indexing behavior.
• Variable Increment: k = k + 1 is used to increment the index variable k in each iteration.
• Function Calls: The Python code calls the same functions (wye_sumeq, kimura_stateq, returnyfe) as the MATLAB code.
• Array Indexing: In Python, array indexing uses [], and [:, k] selects all elements from the first dimension and the kth element from the second dimension.
• Multiplication: * is used for element-wise multiplication in Python.

This demonstrates the straightforward conversion process between MATLAB and Python, preserving the core logic and functionality of the code.