function [VOI, STATES, ALGEBRAIC, CONSTANTS] = mainFunction() % This is the "main function". In Matlab, things work best if you rename this function to match the filename. [VOI, STATES, ALGEBRAIC, CONSTANTS] = solveModel(); end function [algebraicVariableCount] = getAlgebraicVariableCount() % Used later when setting a global variable with the number of algebraic variables. % Note: This is not the "main method". algebraicVariableCount =31; end % There are a total of 6 entries in each of the rate and state variable arrays. % There are a total of 23 entries in the constant variable array. % function [VOI, STATES, ALGEBRAIC, CONSTANTS] = solveModel() % Create ALGEBRAIC of correct size global algebraicVariableCount; algebraicVariableCount = getAlgebraicVariableCount(); % Initialise constants and state variables [INIT_STATES, CONSTANTS] = initConsts; % Set timespan to solve over tspan = [0, 10]; % Set numerical accuracy options for ODE solver options = odeset('RelTol', 1e-06, 'AbsTol', 1e-06, 'MaxStep', 1); % Solve model with ODE solver [VOI, STATES] = ode15s(@(VOI, STATES)computeRates(VOI, STATES, CONSTANTS), tspan, INIT_STATES, options); % Compute algebraic variables [RATES, ALGEBRAIC] = computeRates(VOI, STATES, CONSTANTS); ALGEBRAIC = computeAlgebraic(ALGEBRAIC, CONSTANTS, STATES, VOI); % Plot state variables against variable of integration [LEGEND_STATES, LEGEND_ALGEBRAIC, LEGEND_VOI, LEGEND_CONSTANTS] = createLegends(); figure(); plot(VOI, STATES); xlabel(LEGEND_VOI); l = legend(LEGEND_STATES); set(l,'Interpreter','none'); end function [LEGEND_STATES, LEGEND_ALGEBRAIC, LEGEND_VOI, LEGEND_CONSTANTS] = createLegends() LEGEND_STATES = ''; LEGEND_ALGEBRAIC = ''; LEGEND_VOI = ''; LEGEND_CONSTANTS = ''; LEGEND_VOI = strpad('time in component environment (second)'); LEGEND_CONSTANTS(:,1) = strpad('C_m in component environment (fF)'); LEGEND_STATES(:,1) = strpad('q_Ca_o in component environment (fmol)'); LEGEND_STATES(:,2) = strpad('q_Ca_i in component environment (fmol)'); LEGEND_STATES(:,3) = strpad('q_s00_TCC in component environment (fmol)'); LEGEND_STATES(:,4) = strpad('q_s10_TCC in component environment (fmol)'); LEGEND_STATES(:,5) = strpad('q_s01_TCC in component environment (fmol)'); LEGEND_STATES(:,6) = strpad('q_s11_TCC in component environment (fmol)'); LEGEND_ALGEBRAIC(:,3) = strpad('q_mem in component environment (fC)'); LEGEND_ALGEBRAIC(:,2) = strpad('V_mem in component environment (volt)'); LEGEND_CONSTANTS(:,2) = strpad('R in component environment (J_per_K_per_mol)'); LEGEND_CONSTANTS(:,3) = strpad('T in component environment (kelvin)'); LEGEND_CONSTANTS(:,4) = strpad('F in component environment (C_per_mol)'); LEGEND_ALGEBRAIC(:,23) = strpad('v_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,29) = strpad('I_mem_TCC in component TCC (fA)'); LEGEND_CONSTANTS(:,23) = strpad('I_stim in component environment (fA)'); LEGEND_CONSTANTS(:,5) = strpad('stimPeriod in component environment (second)'); LEGEND_CONSTANTS(:,6) = strpad('stimDuration in component environment (second)'); LEGEND_ALGEBRAIC(:,1) = strpad('tPeriod in component environment (second)'); LEGEND_CONSTANTS(:,7) = strpad('kappa_TCC in component TCC_parameters (fmol_per_sec)'); LEGEND_CONSTANTS(:,8) = strpad('kappa_R1_TCC in component TCC_parameters (fmol_per_sec)'); LEGEND_CONSTANTS(:,9) = strpad('kappa_R2_TCC in component TCC_parameters (fmol_per_sec)'); LEGEND_CONSTANTS(:,10) = strpad('kappa_R3_TCC in component TCC_parameters (fmol_per_sec)'); LEGEND_CONSTANTS(:,11) = strpad('kappa_R4_TCC in component TCC_parameters (fmol_per_sec)'); LEGEND_CONSTANTS(:,12) = strpad('K_Ca_i in component TCC_parameters (per_fmol)'); LEGEND_CONSTANTS(:,13) = strpad('K_Ca_o in component TCC_parameters (per_fmol)'); LEGEND_CONSTANTS(:,14) = strpad('K_S00_TCC in component TCC_parameters (per_fmol)'); LEGEND_CONSTANTS(:,15) = strpad('K_S10_TCC in component TCC_parameters (per_fmol)'); LEGEND_CONSTANTS(:,16) = strpad('K_S01_TCC in component TCC_parameters (per_fmol)'); LEGEND_CONSTANTS(:,17) = strpad('K_S11_TCC in component TCC_parameters (per_fmol)'); LEGEND_CONSTANTS(:,18) = strpad('zCa in component TCC_parameters (dimensionless)'); LEGEND_CONSTANTS(:,19) = strpad('z_df in component TCC_parameters (dimensionless)'); LEGEND_CONSTANTS(:,20) = strpad('z_ff in component TCC_parameters (dimensionless)'); LEGEND_CONSTANTS(:,21) = strpad('z_dr in component TCC_parameters (dimensionless)'); LEGEND_CONSTANTS(:,22) = strpad('z_fr in component TCC_parameters (dimensionless)'); LEGEND_ALGEBRAIC(:,4) = strpad('u_Ca_i in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,5) = strpad('u_Ca_o in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,6) = strpad('V_mem in component TCC (J_per_C)'); LEGEND_ALGEBRAIC(:,7) = strpad('Am_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,21) = strpad('Af_Ca in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,22) = strpad('Ar_Ca in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,19) = strpad('v_s00_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,30) = strpad('v_s10_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,27) = strpad('v_s01_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,31) = strpad('v_s11_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,14) = strpad('v_R1_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,26) = strpad('v_R2_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,18) = strpad('v_R3_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,28) = strpad('v_R4_TCC in component TCC (fmol_per_sec)'); LEGEND_ALGEBRAIC(:,8) = strpad('mu_s00_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,11) = strpad('mu_s10_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,15) = strpad('mu_s01_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,20) = strpad('mu_s11_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,9) = strpad('Af_R1_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,12) = strpad('Ar_R1_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,16) = strpad('Af_R2_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,24) = strpad('Ar_R2_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,10) = strpad('Af_R3_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,17) = strpad('Ar_R3_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,13) = strpad('Af_R4_TCC in component TCC (J_per_mol)'); LEGEND_ALGEBRAIC(:,25) = strpad('Ar_R4_TCC in component TCC (J_per_mol)'); LEGEND_RATES(:,2) = strpad('d/dt q_Ca_i in component environment (fmol)'); LEGEND_RATES(:,1) = strpad('d/dt q_Ca_o in component environment (fmol)'); LEGEND_RATES(:,3) = strpad('d/dt q_s00_TCC in component environment (fmol)'); LEGEND_RATES(:,4) = strpad('d/dt q_s10_TCC in component environment (fmol)'); LEGEND_RATES(:,5) = strpad('d/dt q_s01_TCC in component environment (fmol)'); LEGEND_RATES(:,6) = strpad('d/dt q_s11_TCC in component environment (fmol)'); LEGEND_STATES = LEGEND_STATES'; LEGEND_ALGEBRAIC = LEGEND_ALGEBRAIC'; LEGEND_RATES = LEGEND_RATES'; LEGEND_CONSTANTS = LEGEND_CONSTANTS'; end function [STATES, CONSTANTS] = initConsts() VOI = 0; CONSTANTS = []; STATES = []; ALGEBRAIC = []; CONSTANTS(:,1) = 60000; STATES(:,1) = 0.04653; STATES(:,2) = 0.000001551; STATES(:,3) = 3.653271338425772e-07; STATES(:,4) = 1e-16; STATES(:,5) = 1e-16; STATES(:,6) = 1e-16; CONSTANTS(:,2) = 8.31; CONSTANTS(:,3) = 310; CONSTANTS(:,4) = 96500; CONSTANTS(:,5) = 1; CONSTANTS(:,6) = 0.0001; CONSTANTS(:,7) = 11414.6; CONSTANTS(:,8) = 1266.14; CONSTANTS(:,9) = 4.33488; CONSTANTS(:,10) = 1.34962; CONSTANTS(:,11) = 7.44777; CONSTANTS(:,12) = 28.7976; CONSTANTS(:,13) = 211.182; CONSTANTS(:,14) = 2.10659; CONSTANTS(:,15) = 0.381738; CONSTANTS(:,16) = 615.294; CONSTANTS(:,17) = 111.498; CONSTANTS(:,18) = 2; CONSTANTS(:,19) = 0.876568910405296; CONSTANTS(:,20) = -0.576510778245838; CONSTANTS(:,21) = -0.872117216889333; CONSTANTS(:,22) = 1.73582739545622; CONSTANTS(:,23) = 0.00000; if (isempty(STATES)), warning('Initial values for states not set');, end end function [RATES, ALGEBRAIC] = computeRates(VOI, STATES, CONSTANTS) global algebraicVariableCount; statesSize = size(STATES); statesColumnCount = statesSize(2); if ( statesColumnCount == 1) STATES = STATES'; ALGEBRAIC = zeros(1, algebraicVariableCount); utilOnes = 1; else statesRowCount = statesSize(1); ALGEBRAIC = zeros(statesRowCount, algebraicVariableCount); RATES = zeros(statesRowCount, statesColumnCount); utilOnes = ones(statesRowCount, 1); end ALGEBRAIC(:,2) = piecewise({VOI>=0.00000&VOI<0.400000, - 0.0900000 , VOI>1.10000&VOI<2.10000, - 0.0600000 , VOI>2.20000&VOI<3.10000, 0.0400000 , VOI>3.50000, - 0.0900000 }, - 0.0800000); ALGEBRAIC(:,3) = ALGEBRAIC(:,2).*CONSTANTS(:,1); ALGEBRAIC(:,6) = ALGEBRAIC(:,3)./CONSTANTS(:,1); ALGEBRAIC(:,8) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,14).*STATES(:,3)); ALGEBRAIC(:,9) = ALGEBRAIC(:,8)+ CONSTANTS(:,19).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,11) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,15).*STATES(:,4)); ALGEBRAIC(:,12) = ALGEBRAIC(:,11)+ CONSTANTS(:,21).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,14) = CONSTANTS(:,8).*(exp(ALGEBRAIC(:,9)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,12)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,10) = ALGEBRAIC(:,8)+ CONSTANTS(:,20).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,15) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,16).*STATES(:,5)); ALGEBRAIC(:,17) = ALGEBRAIC(:,15)+ CONSTANTS(:,22).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,18) = CONSTANTS(:,10).*(exp(ALGEBRAIC(:,10)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,17)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,19) = - ALGEBRAIC(:,14) - ALGEBRAIC(:,18); RATES(:,3) = ALGEBRAIC(:,19); ALGEBRAIC(:,7) = CONSTANTS(:,18).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,4) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,12).*STATES(:,2)); ALGEBRAIC(:,20) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,17).*STATES(:,6)); ALGEBRAIC(:,21) = ALGEBRAIC(:,20)+ALGEBRAIC(:,4)+ALGEBRAIC(:,7); ALGEBRAIC(:,5) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,13).*STATES(:,1)); ALGEBRAIC(:,22) = ALGEBRAIC(:,20)+ALGEBRAIC(:,5); ALGEBRAIC(:,23) = piecewise({ALGEBRAIC(:,7)==0.00000, CONSTANTS(:,7).*(exp(ALGEBRAIC(:,21)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,22)./( CONSTANTS(:,2).*CONSTANTS(:,3)))) }, ((( CONSTANTS(:,7).*ALGEBRAIC(:,7))./( CONSTANTS(:,2).*CONSTANTS(:,3)))./(exp(ALGEBRAIC(:,7)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - 1.00000)).*(exp(ALGEBRAIC(:,21)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,22)./( CONSTANTS(:,2).*CONSTANTS(:,3))))); RATES(:,2) = - ALGEBRAIC(:,23); RATES(:,1) = ALGEBRAIC(:,23); ALGEBRAIC(:,16) = ALGEBRAIC(:,15)+ CONSTANTS(:,19).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,24) = ALGEBRAIC(:,20)+ CONSTANTS(:,21).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,26) = CONSTANTS(:,9).*(exp(ALGEBRAIC(:,16)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,24)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,27) = ALGEBRAIC(:,18) - ALGEBRAIC(:,26); RATES(:,5) = ALGEBRAIC(:,27); ALGEBRAIC(:,13) = ALGEBRAIC(:,11)+ CONSTANTS(:,20).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,25) = ALGEBRAIC(:,20)+ CONSTANTS(:,22).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,28) = CONSTANTS(:,11).*(exp(ALGEBRAIC(:,13)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,25)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,30) = ALGEBRAIC(:,14) - ALGEBRAIC(:,28); RATES(:,4) = ALGEBRAIC(:,30); ALGEBRAIC(:,31) = ALGEBRAIC(:,26)+ALGEBRAIC(:,28); RATES(:,6) = ALGEBRAIC(:,31); RATES = RATES'; end % Calculate algebraic variables function ALGEBRAIC = computeAlgebraic(ALGEBRAIC, CONSTANTS, STATES, VOI) statesSize = size(STATES); statesColumnCount = statesSize(2); if ( statesColumnCount == 1) STATES = STATES'; utilOnes = 1; else statesRowCount = statesSize(1); utilOnes = ones(statesRowCount, 1); end ALGEBRAIC(:,2) = piecewise({VOI>=0.00000&VOI<0.400000, - 0.0900000 , VOI>1.10000&VOI<2.10000, - 0.0600000 , VOI>2.20000&VOI<3.10000, 0.0400000 , VOI>3.50000, - 0.0900000 }, - 0.0800000); ALGEBRAIC(:,3) = ALGEBRAIC(:,2).*CONSTANTS(:,1); ALGEBRAIC(:,6) = ALGEBRAIC(:,3)./CONSTANTS(:,1); ALGEBRAIC(:,8) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,14).*STATES(:,3)); ALGEBRAIC(:,9) = ALGEBRAIC(:,8)+ CONSTANTS(:,19).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,11) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,15).*STATES(:,4)); ALGEBRAIC(:,12) = ALGEBRAIC(:,11)+ CONSTANTS(:,21).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,14) = CONSTANTS(:,8).*(exp(ALGEBRAIC(:,9)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,12)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,10) = ALGEBRAIC(:,8)+ CONSTANTS(:,20).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,15) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,16).*STATES(:,5)); ALGEBRAIC(:,17) = ALGEBRAIC(:,15)+ CONSTANTS(:,22).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,18) = CONSTANTS(:,10).*(exp(ALGEBRAIC(:,10)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,17)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,19) = - ALGEBRAIC(:,14) - ALGEBRAIC(:,18); ALGEBRAIC(:,7) = CONSTANTS(:,18).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,4) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,12).*STATES(:,2)); ALGEBRAIC(:,20) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,17).*STATES(:,6)); ALGEBRAIC(:,21) = ALGEBRAIC(:,20)+ALGEBRAIC(:,4)+ALGEBRAIC(:,7); ALGEBRAIC(:,5) = CONSTANTS(:,2).*CONSTANTS(:,3).*log( CONSTANTS(:,13).*STATES(:,1)); ALGEBRAIC(:,22) = ALGEBRAIC(:,20)+ALGEBRAIC(:,5); ALGEBRAIC(:,23) = piecewise({ALGEBRAIC(:,7)==0.00000, CONSTANTS(:,7).*(exp(ALGEBRAIC(:,21)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,22)./( CONSTANTS(:,2).*CONSTANTS(:,3)))) }, ((( CONSTANTS(:,7).*ALGEBRAIC(:,7))./( CONSTANTS(:,2).*CONSTANTS(:,3)))./(exp(ALGEBRAIC(:,7)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - 1.00000)).*(exp(ALGEBRAIC(:,21)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,22)./( CONSTANTS(:,2).*CONSTANTS(:,3))))); ALGEBRAIC(:,16) = ALGEBRAIC(:,15)+ CONSTANTS(:,19).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,24) = ALGEBRAIC(:,20)+ CONSTANTS(:,21).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,26) = CONSTANTS(:,9).*(exp(ALGEBRAIC(:,16)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,24)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,27) = ALGEBRAIC(:,18) - ALGEBRAIC(:,26); ALGEBRAIC(:,13) = ALGEBRAIC(:,11)+ CONSTANTS(:,20).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,25) = ALGEBRAIC(:,20)+ CONSTANTS(:,22).*CONSTANTS(:,4).*ALGEBRAIC(:,6); ALGEBRAIC(:,28) = CONSTANTS(:,11).*(exp(ALGEBRAIC(:,13)./( CONSTANTS(:,2).*CONSTANTS(:,3))) - exp(ALGEBRAIC(:,25)./( CONSTANTS(:,2).*CONSTANTS(:,3)))); ALGEBRAIC(:,30) = ALGEBRAIC(:,14) - ALGEBRAIC(:,28); ALGEBRAIC(:,31) = ALGEBRAIC(:,26)+ALGEBRAIC(:,28); ALGEBRAIC(:,1) = VOI - floor(VOI./CONSTANTS(:,5)).*CONSTANTS(:,5); ALGEBRAIC(:,29) = CONSTANTS(:,4).*( - CONSTANTS(:,18).*ALGEBRAIC(:,23)+ ALGEBRAIC(:,14).*(CONSTANTS(:,21) - CONSTANTS(:,19))+ ALGEBRAIC(:,26).*(CONSTANTS(:,21) - CONSTANTS(:,19))+ ALGEBRAIC(:,18).*(CONSTANTS(:,22) - CONSTANTS(:,20))+ ALGEBRAIC(:,28).*(CONSTANTS(:,22) - CONSTANTS(:,20))); end % Compute result of a piecewise function function x = piecewise(cases, default) set = [0]; for i = 1:2:length(cases) if (length(cases{i+1}) == 1) x(cases{i} & ~set,:) = cases{i+1}; else x(cases{i} & ~set,:) = cases{i+1}(cases{i} & ~set); end set = set | cases{i}; if(set), break, end end if (length(default) == 1) x(~set,:) = default; else x(~set,:) = default(~set); end end % Pad out or shorten strings to a set length function strout = strpad(strin) req_length = 160; insize = size(strin,2); if insize > req_length strout = strin(1:req_length); else strout = [strin, blanks(req_length - insize)]; end end