Interpolation input grid is not a valid meshgrid

2021 12 21
1 个回答
回答已采纳
更新时间：2021 12 21
8 次查看（30 天）

0 个投票

Hi,
I'm quite new to MATLAB and i can't figure out what i'm doing wrong.
omega=... % speed in rad/s
((1/3.6)/0.0625)*[2 2 2 2 2;
4 4 4 4 4;
6 6 6 6 6;
8 8 8 8 8;
10 10 10 10 10;
12 12 12 12 12;
14 14 14 14 14;
16 16 16 16 16;
18 18 18 18 18;
20 20 20 20 20;
22 22 22 22 22;
24 24 24 24 24;
26 26 26 26 26;
28 28 28 28 28;
30 30 30 30 30;
32 32 32 32 32;
34 34 34 34 34;
36 36 36 36 36;
38 38 38 38 38];
torque=... % torque in Nm
0.04*[5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ;
5 7 10 13 15 ];
eta=... % measured efficiency
[0.1025 0.1440 0.1824 0.2076 0.2190 ;
0.1338 0.1929 0.2463 0.2804 0.2975 ;
0.1461 0.2147 0.2790 0.3267 0.3378 ;
0.1246 0.2255 0.2658 0.3470 0.3414 ;
0.1380 0.2254 0.2919 0.3724 0.3691 ;
0.1427 0.2501 0.3000 0.3840 0.5545 ;
0.3453 0.4437 0.5122 0.3896 0.5680 ;
0.3439 0.4464 0.5247 0.3944 0.5810 ;
0.3435 0.4549 0.5319 0.3968 0.5883 ;
0.3487 0.4659 0.5449 0.4005 0.6039 ;
0.3462 0.2500 0.5521 0.4071 0.6104 ;
0.1481 0.2423 0.3356 0.4058 0.4239 ;
0.1495 0.2480 0.3382 0.4070 0.4213 ;
0.1491 0.2491 0.3359 0.4097 0.4186 ;
0.1516 0.2531 0.3456 0.4122 0.4195 ;
0.1514 0.2573 0.3478 0.4330 0.4042 ;
0.1507 0.2584 0.3532 0.4232 0.3923 ;
0.1523 0.2582 0.3540 0.4252 0.3999 ;
0.1463 0.2617 0.3572 0.4267 0.4923 ];
%Interpolate to refine data
[omega_q , torque_q]=meshgrid ((((1/3.6)/0.0625)*2):((1/3.6)/0.0625):(((1/3.6)/0.0625)*38), (5*0.04):0.04:(15*0.04)); % set refined points
eta_q=interp2(omega, torque , eta , omega_q , torque_q, 'cubic'); % do cubic interpolation
I know I defined the meshgrid in a really weird way. But i just don't know what to do. If someone could help I would be really gratefull.
Thanks in advance!
Thom Nelissen

请先登录，再回答此问题。

 采纳的回答

Stephen23
Stephen23 2021-12-21
编辑：Stephen23 2021-12-21
Ran in:

0 个投票

Ran in:
You mixed up the dimensions. This follows the explanation and examples in the INTERP2 documentation:
omega = ((1/3.6)/0.0625)*[2,2,2,2,2;4,4,4,4,4;6,6,6,6,6;8,8,8,8,8;10,10,10,10,10;12,12,12,12,12;14,14,14,14,14;16,16,16,16,16;18,18,18,18,18;20,20,20,20,20;22,22,22,22,22;24,24,24,24,24;26,26,26,26,26;28,28,28,28,28;30,30,30,30,30;32,32,32,32,32;34,34,34,34,34;36,36,36,36,36;38,38,38,38,38]
omega = 19×5
8.8889 8.8889 8.8889 8.8889 8.8889 17.7778 17.7778 17.7778 17.7778 17.7778 26.6667 26.6667 26.6667 26.6667 26.6667 35.5556 35.5556 35.5556 35.5556 35.5556 44.4444 44.4444 44.4444 44.4444 44.4444 53.3333 53.3333 53.3333 53.3333 53.3333 62.2222 62.2222 62.2222 62.2222 62.2222 71.1111 71.1111 71.1111 71.1111 71.1111 80.0000 80.0000 80.0000 80.0000 80.0000 88.8889 88.8889 88.8889 88.8889 88.8889
torque = 0.04*[5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15;5,7,10,13,15]
torque = 19×5
0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000 0.2000 0.2800 0.4000 0.5200 0.6000
eta = [0.1025,0.1440,0.1824,0.2076,0.2190;0.1338,0.1929,0.2463,0.2804,0.2975;0.1461,0.2147,0.2790,0.3267,0.3378;0.1246,0.2255,0.2658,0.3470,0.3414;0.1380,0.2254,0.2919,0.3724,0.3691;0.1427,0.2501,0.3000,0.3840,0.5545;0.3453,0.4437,0.5122,0.3896,0.5680;0.3439,0.4464,0.5247,0.3944,0.5810;0.3435,0.4549,0.5319,0.3968,0.5883;0.3487,0.4659,0.5449,0.4005,0.6039;0.3462,0.2500,0.5521,0.4071,0.6104;0.1481,0.2423,0.3356,0.4058,0.4239;0.1495,0.2480,0.3382,0.4070,0.4213;0.1491,0.2491,0.3359,0.4097,0.4186;0.1516,0.2531,0.3456,0.4122,0.4195;0.1514,0.2573,0.3478,0.4330,0.4042;0.1507,0.2584,0.3532,0.4232,0.3923;0.1523,0.2582,0.3540,0.4252,0.3999;0.1463,0.2617,0.3572,0.4267,0.4923]
eta = 19×5
0.1025 0.1440 0.1824 0.2076 0.2190 0.1338 0.1929 0.2463 0.2804 0.2975 0.1461 0.2147 0.2790 0.3267 0.3378 0.1246 0.2255 0.2658 0.3470 0.3414 0.1380 0.2254 0.2919 0.3724 0.3691 0.1427 0.2501 0.3000 0.3840 0.5545 0.3453 0.4437 0.5122 0.3896 0.5680 0.3439 0.4464 0.5247 0.3944 0.5810 0.3435 0.4549 0.5319 0.3968 0.5883 0.3487 0.4659 0.5449 0.4005 0.6039
%Interpolate to refine data
V1 = (5*0.04):0.04:(15*0.04);
V2 = ((1/3.6)/0.0625)*2:(1/3.6)/0.0625:((1/3.6)/0.0625)*38;
[torque_q,omega_q] = meshgrid(V1, V2) % swap the order here !!!!
torque_q = 37×11
0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000 0.2000 0.2400 0.2800 0.3200 0.3600 0.4000 0.4400 0.4800 0.5200 0.5600 0.6000
omega_q = 37×11
8.8889 8.8889 8.8889 8.8889 8.8889 8.8889 8.8889 8.8889 8.8889 8.8889 8.8889 13.3333 13.3333 13.3333 13.3333 13.3333 13.3333 13.3333 13.3333 13.3333 13.3333 13.3333 17.7778 17.7778 17.7778 17.7778 17.7778 17.7778 17.7778 17.7778 17.7778 17.7778 17.7778 22.2222 22.2222 22.2222 22.2222 22.2222 22.2222 22.2222 22.2222 22.2222 22.2222 22.2222 26.6667 26.6667 26.6667 26.6667 26.6667 26.6667 26.6667 26.6667 26.6667 26.6667 26.6667 31.1111 31.1111 31.1111 31.1111 31.1111 31.1111 31.1111 31.1111 31.1111 31.1111 31.1111 35.5556 35.5556 35.5556 35.5556 35.5556 35.5556 35.5556 35.5556 35.5556 35.5556 35.5556 40.0000 40.0000 40.0000 40.0000 40.0000 40.0000 40.0000 40.0000 40.0000 40.0000 40.0000 44.4444 44.4444 44.4444 44.4444 44.4444 44.4444 44.4444 44.4444 44.4444 44.4444 44.4444 48.8889 48.8889 48.8889 48.8889 48.8889 48.8889 48.8889 48.8889 48.8889 48.8889 48.8889
eta_q = interp2(torque, omega, eta, torque_q, omega_q, 'spline') % do cubic interpolation
eta_q = 37×11
0.1025 0.1254 0.1440 0.1592 0.1717 0.1824 0.1919 0.2003 0.2076 0.2138 0.2190 0.1171 0.1493 0.1729 0.1902 0.2032 0.2144 0.2255 0.2363 0.2466 0.2557 0.2632 0.1338 0.1665 0.1929 0.2143 0.2317 0.2463 0.2591 0.2704 0.2804 0.2894 0.2975 0.1457 0.1777 0.2061 0.2309 0.2523 0.2704 0.2854 0.2976 0.3076 0.3157 0.3223 0.1461 0.1842 0.2147 0.2394 0.2602 0.2790 0.2971 0.3134 0.3267 0.3353 0.3378 0.1331 0.1873 0.2207 0.2408 0.2549 0.2703 0.2923 0.3168 0.3378 0.3490 0.3443 0.1246 0.1900 0.2255 0.2425 0.2521 0.2658 0.2912 0.3217 0.3470 0.3570 0.3414 0.1340 0.1935 0.2289 0.2493 0.2639 0.2819 0.3091 0.3386 0.3598 0.3626 0.3366 0.1380 0.1903 0.2254 0.2498 0.2698 0.2919 0.3202 0.3495 0.3724 0.3814 0.3691 0.1219 0.1810 0.2182 0.2415 0.2588 0.2780 0.3055 0.3403 0.3800 0.4219 0.4636

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Interpolation 的更多信息

产品

版本

R2021b

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by