Hi 泰誠 平山,
私の母国語は日本語ではないので、この質問には英語で答えます。ご理解のほどよろしくお願いいたします。.
I understand that you want to fit the equation-"A" to the provided data in MATLAB and further want to find the values of the coefficients of the equation.
Follow the below steps to fit the curve to the given data:
- Define two arrays - "hc" and "Ahc" representing the variable values and its corresponding function values respectively.
- Next, Use the "fittype" function to define the equation and the independent parameter of the equation.
- Further, Use the "fit" function to perform the curve fitting the with initial guesses for the coefficients (c1-c8) as an array of zeros.
- Finally, extract the coefficients from the fitted model.
Here is the detailed code snippet for your reference-
hc = [437.8721, 441.0834, 452.8841, 436.7682, 437.9955, 448.4398, 455.7468, 443.8015, 525.4903, 538.895, 537.2546, 525.2589, 516.5977, 526.974, 537.6951, 531.9221, 604.8993, 609.551, 602.9513, 596.8787, 601.4953, 598.9064, 606.6538, 596.7564, 668.5769, 699.6305, 678.4585, 670.5805, 680.9208, 679.8531, 673.3044, 694.1689, 756.6379, 745.3489, 750.0761, 748.371, 748.7925, 752.3254, 752.9984, 759.1911, 847.7004, 842.3609, 841.6435, 836.3349, 828.2203, 838.1522, 839.4045, 838.6771, 1203.12, 1206.318, 1197.958, 1218.17, 1223.971, 1204.434, 1217.797, 1210.291, 1543.912, 1536.93, 1542.479, 1546.797, 1544.828, 1535.265, 1530.165, 1532.803, 1818.71, 1898.994, 1869.862, 1894.521, 1875.092, 1905.734, 1891.786, 1882.396, 1901.279, 1860.508, 1949.379, 1967.343, 1884.619, 1923.635, 2025.482, 2032.288];
A_hc = [0.00047, 0.000408, 0.000467, 0.00043, 0.000388, 0.00039, 0.000353, 0.000357, 0.000531, 0.000308, 0.000402, 0.000432, 0.00039, 0.000391, 0.000371, 0.000404, 0.000372, 0.000372, 0.000353, 0.000364, 0.00039, 0.000387, 0.0004, 0.000363, 0.000298, 0.000369, 0.000301, 0.000362, 0.000344, 0.000313, 0.00029, 0.00035, 0.000324, 0.000296, 0.000278, 0.000302, 0.000299, 0.00031, 0.000277, 0.000282, 0.000185, 0.00025, 0.000243, 0.000238, 0.00024, 0.000228, 0.000272, 0.000229, 0.000132, 0.000148, 0.000149, 9.87E-05, 8.72E-05, 0.000127, 8.05E-05, 8.99E-05, 0.000128, 0.000133, 0.000127, 0.000124, 0.000116, 0.000126, 0.000128, 0.000132, 0.000159, 8.88E-05, 0.00011, 7.62E-05, 9.29E-05, 5.55E-05, 7.67E-05, 9.71E-05, 0.000139, 0.000195, 0.000112, 0.000107, 0.000206, 0.000148, 7.88E-05, 8.1E-05];
fitFunction = fittype('24.5*x^2 + c1*x + c2*sqrt(x) + c3*x^(1/4) + c4*x^(1/8) + c5*x^(1/16) + c6*x^(1/32) + c7*x^(1/64) + c8*x^(1/128)', 'independent', 'x');
fittedModel = fit(hc', A_hc', fitFunction, 'StartPoint', [0, 0, 0, 0, 0, 0, 0, 0]);
c1 = fittedModel.c1;
c2 = fittedModel.c2;
c3 = fittedModel.c3;
c4 = fittedModel.c4;
c5 = fittedModel.c5;
c6 = fittedModel.c6;
c7 = fittedModel.c7;
c8 = fittedModel.c8;
Additionally, refer to the following documentations for more details on how to use the above mentioned functions-
Hope this helps you in understanding how to perform curve fitting in MATLAB.
