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1135725495鐵桿木蟲 (著名寫手)
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[求助]
matlab 已有1人參與
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用matlab軟件計(jì)算置信區(qū)間,算出來的結(jié)果過大怎么解決??? @月只藍(lán) |
主管區(qū)長 (職業(yè)作家)
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專家經(jīng)驗(yàn): +1059 |

主管區(qū)長 (職業(yè)作家)
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專家經(jīng)驗(yàn): +1059 |

鐵桿木蟲 (著名寫手)
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你好!以下是用matlab計(jì)算的結(jié)果,使用的ci = nlparci(k,residual,jacobian)函數(shù),置信度為95%。算出來的決定系數(shù)在0.9以上呢。算出來的置信區(qū)間好大啊,不知問題出在哪? ci = 1.0e+03 * -0.1666 0.1667 -0.0000 0.0000 -0.1562 0.1562 -6.0471 6.0552 以fmincon()的結(jié)果為初值,使用函數(shù)lsqnonlin()估計(jì)得到的參數(shù)值為: k1 = 0.05881980024 k2 = 0.00000000000 k3 = 0.00396318725 k4 = 4.05955359944 The sum of the squares is: 6.0e-06 output = firstorderopt: 6.1534e-07 iterations: 1 funcCount: 10 cgiterations: 0 algorithm: 'trust-region-reflective' message: [1x425 char] |
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鐵桿木蟲 (著名寫手)
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下面是程序,方程 r1 =-dc/dt=(k(1)*c^2-0.25*k(2)*(9.404-c)^2)/(1+k(3)*c+0.5*k(4)*(9.404-c))^2,數(shù)據(jù)是c關(guān)于t的方程,因變化量c,自變量是t,待估計(jì)參數(shù)k(1),k(2),k(3),k(4) function parafit % % r1 =(k(1)*c^2-0.25*k(2)*(9.404-c)^2)/(1+k(3)*c+0.5*k(4)*(9.404-c))^2; % % dCAdt = - r1; clear all clc % t/min CA / mol/L Kinetics=[0 8.8599786 3 7.81716904 6 7.3661532 9 7.062404 12 6.82862056 15 6.63696704 18 6.47380764 21 6.33133704 31 5.95301412 41 5.6663802 51 5.43447756 61 5.23953264]; k0 = [0.04539 0.008031 0.07300 3.0230]; % 參數(shù)初值 lb = [0 0 0 0]; % 參數(shù)下限 ub =[1 1 1 10]; % 參數(shù)上限 x0 = [8.8599786]; yexp = Kinetics; warning off % 使用函數(shù)fmincon()進(jìn)行參數(shù)估計(jì) [k,fval,flag] = fmincon(@ObjFunc7Fmincon,k0,[],[],[],[],lb,ub,[],[],x0,yexp); fprintf('\n使用函數(shù)fmincon()估計(jì)得到的參數(shù)值為:\n') fprintf('\tk1 = %.11f\n',k(1)) fprintf('\tk2 = %.11f\n',k(2)) fprintf('\tk3 = %.11f\n',k(3)) fprintf('\tk4 = %.11f\n',k(4)) fprintf(' The sum of the squares is: %.1e\n\n',fval) k_fm= k; warning off % 使用函數(shù)lsqnonlin()進(jìn)行參數(shù)估計(jì) [k,resnorm,residual,exitflag,output,lambda, jacobian,] = ... lsqnonlin(@ObjFunc7LNL,k0,lb,ub,[],x0,yexp); ci = nlparci(k,residual,jacobian) fprintf('\n\n使用函數(shù)lsqnonlin()估計(jì)得到的參數(shù)值為:\n') fprintf('\tk1 = %.11f\n',k(1)) fprintf('\tk2 = %.11f\n',k(2)) fprintf('\tk3 = %.11f\n',k(3)) fprintf('\tk4 = %.11f\n',k(4)) fprintf(' The sum of the squares is: %.1e\n\n',resnorm) k_ls = k; output warning off % 以函數(shù)fmincon()估計(jì)得到的結(jié)果為初值,使用函數(shù)lsqnonlin()進(jìn)行參數(shù)估計(jì) k0 = k_fm; [k,resnorm,residual,exitflag,output,lambda,jacobian] = ... lsqnonlin(@ObjFunc7LNL,k0,lb,ub,[],x0,yexp); ci = nlparci(k,residual,jacobian) fprintf('\n\n以fmincon()的結(jié)果為初值,使用函數(shù)lsqnonlin()估計(jì)得到的參數(shù)值為:\n') fprintf('\tk1 = %.11f\n',k(1)) fprintf('\tk2 = %.11f\n',k(2)) fprintf('\tk3 = %.11f\n',k(3)) fprintf('\tk4 = %.11f\n',k(4)) fprintf(' The sum of the squares is: %.1e\n\n',resnorm) k_fmls = k; output tspan = [0 3 6 9 12 15 18 21 31 41 51 61]; [t x] = ode45(@KineticEqs,tspan,x0,[],k_fmls); figure; plot(t,x,'o-',t,yexp(:,2),'*');legend('Predictive value','Experimental data') x % ------------------------------------------------------------------ function f = ObjFunc7Fmincon(k,x0,yexp) tspan = [0 3 6 9 12 15 18 21 31 41 51 61]; [t x] = ode45(@KineticEqs,tspan,x0,[],k); f = sum((x-yexp(:,2)).^2) ; % ------------------------------------------------------------------ function f = ObjFunc7LNL(k,x0,yexp) tspan = [0 3 6 9 12 15 18 21 31 41 51 61]; [t x] = ode45(@KineticEqs,tspan,x0,[],k); f1 = x - yexp(:,2); f = [f1]; % ------------------------------------------------------------------ function dxdt = KineticEqs(t,x,k) dxdt=-(k(1)*x^2-0.25*k(2)*(9.404-x)^2)/(1+k(3)*x+0.5*k(4)*(9.404-x))^2; |
鐵桿木蟲 (著名寫手)
主管區(qū)長 (職業(yè)作家)
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專家經(jīng)驗(yàn): +1059 |

鐵桿木蟲 (著名寫手)
主管區(qū)長 (職業(yè)作家)
![]() |
專家經(jīng)驗(yàn): +1059 |

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