matlab oop "use data of hole class" for calculation - matlab

First, sorry for the bad title - I'm new to OO programming - basically I'd like to understand how Matlab works with oop classes.
Before I ask my question, here is a basic example of what I want to do:
I have two houses and some data about them and I got the idea, to work with oop classes. Here is my .m file.
classdef building
properties
hohe = 0;
lange = 0;
breite = 0;
xabstandsolar = 0;
yabstandsolar = 0;
end
methods
function obj = building(hohe, lange, breite, xabstandsolar, yabstandsolar)
obj.hohe = hohe;
obj.lange = lange;
obj.breite = breite;
obj.xabstandsolar = xabstandsolar;
obj.yabstandsolar = yabstandsolar;
end
function hohenwinkel(h)
h = h
d = sqrt(obj.xabstandsolar^2 + yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
end
end
end
I filled it with some data - for example
>>H1 = building(10,8,6,14,8)
>>H2 = building(18,8,6,14,0)
And now I want to calculate "gamma_v" (as an 1x2 array) for each building. Any ideas, how I can archive this?
Edit:
I want to create gamma_v (as an array) automatically for all objects in the class "building". There will be a lot more "houses" in the final script.

Your hohenwinkel method needs to accept two input arguments. The first argument for non-static methods is always the object itself (unlike C++, you'll have to explicitly list it as an input argument) and the second input will be your h variable. You'll also want to actually return the gamma_v value using an output argument for your method.
function gamma_v = hohenwinkel(obj, h)
d = sqrt(obj.xabstandsolar^2 + obj.yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
end
Then you can invoke this method on each building to get the value
gamma_v1 = hohenwinkel(H1);
gamma_v2 = hohenwinkel(H2);
If you want to have an array of buildings, you can create that array
houses = [building(10,8,6,14,8), building(18,8,6,14,0)];
gamma_v = hohenwinkel(houses);
and then construct your hohenwinkel function to operate on each one and return the result
function gamma_v = hohenwinkel(obj, h)
if numel(obj) > 1
% Compute hohenwinkel for each one
gamma_v = arrayfun(#(x)hohenwinkel(x, h), obj);
return
end
d = sqrt(obj.xabstandsolar^2 + obj.yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
end

there is some tricky solution (and its not recommended)(#Suever solution is better)
you should create a handle class
classdef gvclass<handle
properties
gvarr=[];
end
methods
function setgvarr(obj,value)
obj.gvarr=[obj.gvarr,value];
end
end
end
then use this class in your building class
classdef building<handle
properties
gv
hohe = 0;
lange = 0;
breite = 0;
xabstandsolar = 0;
yabstandsolar = 0;
end
methods
function obj = building(hohe, lange, breite, xabstandsolar, yabstandsolar,handle_of_your_gv_class,h)
obj.hohe = hohe;
obj.lange = lange;
obj.breite = breite;
obj.xabstandsolar = xabstandsolar;
obj.yabstandsolar = yabstandsolar;
obj.gv=handle_of_your_gv_class;
obj.hohenwinkel(h);
end
function hohenwinkel(obj,h)
d = sqrt(obj.xabstandsolar^2 + yabstandsolar^2);
gamma_v = atand((obj.hohe - h)/(d));
obj.gv.setgvarr(gamma_v);
end
end
end
finally before creating any building you should create an object of gv class and pass it to the building constructor,
Egv=gvclass();
H1 = building(10,8,6,14,8,Egv,2)
H2 = building(18,8,6,14,0,Egv,3)
and to access gv array:
Egv.gvarr
you should do more effort on this issue to debug possible errors.

Related

Proper usage of lua tables/classes

I'm trying to use class behavior in lua where there is a ship that has two other classes pos and vector
But I cannot get it working like I assumed I would be able to
Point = {x=0, y=0}
function Point:new(p)
p = p or {}
return p
end
Ship =
{
pos = {Point:new{x=0,y=0}},
vector = {Point:new{x=0,y=0}} -- I thought this would be sufficient for access being available for vector
}
-- create new ship class
function Ship:new(pos)
p = p or {}
p.pos = pos
p.vector = Point:new{x=0,y=0} -- I need to do this or accessing vector will crash (The problem)
return p
end
-- Create new ship...
plrShip = Ship:new{}
plrShip.pos.x = 300
plrShip.pos.y = 300
If anyone knows how to make the above code cleaner/better I would be thankful
You can use metatables to set default fields. (I've made some assumptions about what you're trying to do. If this doesn't work for you, please add some clarification to your question.)
local Point = {x=0, y=0}
Point.__index = Point
function Point:new(p)
p = p or {}
setmetatable(p, self)
return p
end
-- create new ship class
local Ship = {}
Ship.__index = Ship
function Ship:new(pos)
setmetatable(pos, Point)
local p = {pos = pos, vector = Point:new()}
setmetatable(p, self)
return p
end
-- Create new ship...
local plrShip = Ship:new{}
plrShip.pos.x = 300
plrShip.pos.y = 300
I found solution to do this, it still not perfect but only I got working was this modified code:
Ship =
{
pos = Point:new{x=0,y=0},
vector = Point:new{x=0,y=0}
}
function Ship:new()
p = p or {}
p.pos = self.pos
p.vector = self.vector
return p
end
plrShip = Ship:new()
plrShip.pos.x = 300
plrShip.pos.y = 300

How to generalize Matlab function?

I have a Matlab function. I need to generalize this function. This code’s aim is to check this IndicMPs are in the TableTemp, if it is there, then we extract relevant age limits, such as: Age_Limite_DC, Age_Limite_IT, Age_Limite_Ch and Transfert_Prime_IT_DC. My idea is to generalize, passing parameters to find out the "Type_pret" is.(May be I'm wrong) Since I'm beginner to Matlab can someone help me to encode a more generic function that can be used in a more general context?
function Structure = optimisation_function()
Data = load('Data.mat');
Structure = Data.Structure;
TableTemp = Data.TableTemp;
Age_Limite_DC = zeros(size(Structure,1),1);
Age_Limite_IT = zeros(size(Structure,1),1);
Age_Limite_CH = zeros(size(Structure,1),1);
Transfert_Prime_IT_DC = zeros(size(Structure,1),1);
for IndexMPAL = 1 : length(Structure.AnneeSouscription)
% Determine Type_Pret (Loan Type)
if ~isempty(strfind(Structure.Type_Pret{IndexMPAL},'A'))
Type_Pret = 'A';
elseif ~isempty(strfind(Structure.Type_Pret{IndexMPAL},'B'))
Type_Pret = 'B';
elseif ~isempty(strfind(Structure.Type_Pret{IndexMPAL},'C'))
Type_Pret = 'C';
elseif ~isempty(strfind(Structure.Type_Pret{IndexMPAL},'D'))
Type_Pret = 'D';
elseif ~isempty(strfind(Structure.Type_Pret{IndexMPAL},'E'))
Type_Pret = 'E';
end
MP_CP = Structure.NomCodeProduit(IndexMPAL);
MP_AnSous = Structure.AnneeSouscription(IndexMPAL);
MP_TypePret = Type_Pret;
IndicCP = strcmp(MP_CP, TableTemp.CodeProduit);
IndicAS = MP_AnSous== TableTemp.AnneeSouscription;
IndicTP = strcmp(MP_TypePret, TableTemp.TypePret);
IndicMP = IndicCP & IndicAS & IndicTP;
if ~any(IndicMP)
Msg = strcat('CodeProduct:',MP_CP{1}, ', Année Souscription:', num2str(MP_AnSous), ', Type Prêt:', MP_TypePret);
error('Error', Msg)
else
Age_Limite_DC(IndexMPAL,1) = TableTemp.Age_Limite_DC(IndicMP,1);
Age_Limite_IT(IndexMPAL,1) = TableTemp.Age_Limite_IT(IndicMP,1);
Age_Limite_CH(IndexMPAL,1) = TableTemp.Age_Limite_CH(IndicMP,1);
Transfert_Prime_IT_DC(IndexMPAL,1)=
TableTemp.Transfert_Prime_IT_DC(IndicMP,1);
end
end
Structure.Age_Limite_DC = Age_Limite_DC;
Structure.Age_Limite_IT = Age_Limite_IT;
Structure.Age_Limite_CH = Age_Limite_CH;
Structure.Transfert_Prime_IT_DC = Transfert_Prime_IT_DC;
end
The if/elseif can be simplified with a cell array:
liststr = {'A','BB','C','D','E'}; % builds a cell array, each cell contains a string
Positive_matches = strfind(liststr,Structure.Type_Pret{IndexMPAL}) % returns a list for each cell of the indices where the element was found (empty if none)
Index = find(~cellfun('isempty', Positive_matches )) % converts the previous list into a logical 0/1 array indicating whether an item was found (1) or not (0)
% if isempty(Index); continue; end % If no index is found, to avoid an error in the next instruction, skips the rest of the code.
Type_Pret = liststr(Index(1));
If the Type_Pret are the same in your list and in Structure? , you can usestrcmp`:
liststr = {'A','B','C','D','E'};
if any(strcmp(Structure.Type_Pret,liststr))
Type_Pret = Structure.Type_Pret
else
% handle error
end
You can also work directly on Structure.Age_Limite_DC without using Age_Limite_DC.

Fit with the parameter

I am quite new to Matlab and I am trying to use this code I found online.
I am trying to fit a graph described by the HydrodynamicSpectrum. But instead of having it fit after inputting fvA and fmA, I am trying to obtain the fitted parameters for this value also.
I have tried removing them, changing them. But none is working. I was wondering if any one here will be able to point me into the right direction of fixing this.
specFunc = #(f, para)HydrodynamicSpectrum(f, [para fvA fmA]);
[fit.AXfc, fit.AXD] = NonLinearFit(fit.f(indXY), fit.AXSpec(indXY), specFunc, [iguess_AXfc iguess_AXD]);
[fit.AYfc, fit.AYD] = NonLinearFit(fit.f(indXY), fit.AYSpec(indXY), specFunc, [iguess_AYfc iguess_AYD]);
[fit.ASumfc, fit.ASumD] = NonLinearFit(fit.f(indSum), fit.ASumSpec(indSum), specFunc, [iguess_ASumfc iguess_ASumD]);
predictedAX = HydrodynamicSpectrum(fit.f, [fit.AXfc fit.AXD fvA fmA]);
predictedAY = HydrodynamicSpectrum(fit.f, [fit.AYfc fit.AYD fvA fmA]);
predictedASum = HydrodynamicSpectrum(fit.f, [fit.ASumfc fit.ASumD fvA fmA]);
function spec = HydrodynamicSpectrum(f, para);
fc = para(1);
D = para(2);
fv = para(3);
fm = para(4);
f = abs(f); %Kludge!
spec = D/pi^2*(1+sqrt(f/fv))./((fc - f.*sqrt(f./fv) - (f.^2)/fm).^2 + (f + f.*sqrt(f./fv)).^2);
function [fc, D, sfc, sD] = NonLinearFit(f, spec, specFunc, init);
func = #(para, f)spec./specFunc(f, para);
[paraFit, resid, J] = nlinfit(f, ones(1, length(spec)), func, init);
fc = paraFit(1);
D = paraFit(2);
ci = nlparci(real(paraFit), real(resid), real(J)); % Kludge!!
sfc = (ci(1,2) - ci(1,1))/4;
sD = (ci(2,2) - ci(2,1))/4;
[paraFit, resid, J] = nlinfit(f, ones(1, length(spec)), func, init);
It looks like you get your fitted parameter using this line. And you are further processing them to get other stuff out from the function. You can modify your second function to get them out as well.
As there are very few comments, and questions seems to be application specific, there is not much help I can give with what you have presented.

Class specific data files in matlab

I'm writing a matlab class which uses data from a .mat-file.
Is there any way I can place this data file inside the class directory structure and make it accessible only to my class?
I.e. I have a directory structure like this:
./MATLAB
+myPackage
#MyClass
MyClass.m
where MyClass.m looks like
classdef MyClass
methods
function y = getValue(obj, x)
load datafile.mat
y = interp1(datax, datay, x);
end
end
end
This works great as long as datafile.mat is in my working directory, but I'd like to move it to +myPackage/#MyClass/datafile.mat instead (or better yet +myPackage/datafile.mat). How would I make my class(es) find it there?
First, you may put the data file in a 'private' subfolder inside your directory structure:
./MATLAB
+myPackage
private
datafile.mat
#MyClass
MyClass.m
NB: This won't garantee that it is only accessible to your class, anyway it will be classified close to your class definition.
Then, you can find back data values like this in your method:
classdef MyClass
methods
function y = getValue(obj, x)
% Find back datafile name
localPath = fileparts(mfilename('fullpath'));
dataFilename = fullfile(localpath, '..', 'private', 'datafile.mat'); % '..' is to go up one folder, up to you to place th file somewhere else (e.g. under +MyPackage directly)
% Read file
data = load(dataFilename);
datax = data.datax;
datay = data.datay;
y = interp1(datax, datay, x);
end
end
end
EDIT: Example with Resources class
Here is an example with separate resource class to avoid loading file data each time getValue is called. I also added for the case you need to care if the file has been modified or not:
classdef Resources
methods(Static)
function [resource] = GetResource(name, careForUpdates)
%[
if (nargin < 2), careForUpdates = true; end
if (nargin < 1), error('Not enough input arguments.'); end
persistent cache;
if (isempty(cache)), cache = containers.Map('UniformValues', false); end
filename = Resources.GetFileName(name);
lastModified = dir(filename);
lastModified = datenum(lastModified.date);
if (~cache.isKey(name) || ...
(careForUpdates && (cache(name).LastModified < lastModified)))
data.LastModified = lastModified;
data.Value = load(filename);
cache(name) = data;
end
resource = cache(name).Value;
%]
end
end
methods(Static, Access=private)
function [fname] = GetFileName(name)
%[
persistent cache;
if (isempty(cache)), cache = containers.Map('UniformValues', false); end
if (~cache.isKey(name))
localpath = fileparts(mfilename('fullpath'));
switch(name)
case 'titi', cache(name) = fullfile(localpath, 'titi.mat');
case 'toto', cache(name) = fullfile(localpath, 'toto.mat');
case 'tata', cache(name) = fullfile(localpath, 'tata.mat');
otherwise, error('Resource `%s` is unknown', name)
end
end
fname = cache(name);
%]
end
end
end
This can be used like this
data = Resources.Get('titi');
Or, if not interested by file updates:
careForFileUpdates = false;
data = Resources.Get('titi', careForFileUpdates);

Recursive concatenation of Matlab structs

Is it somehow possible to concatenate two matlab structures recursively without iterating over all leaves of one of the structures.
For instance
x.a=1;
x.b.c=2;
y.b.d=3;
y.a = 4 ;
would result in the following
res = mergeStructs(x,y)
res.a=4
res.b.c=2
res.b.d=3
The following function works for your particular example. There will be things it doesn't consider, so let me know if there are other cases you want it to work for and I can update.
function res = mergeStructs(x,y)
if isstruct(x) && isstruct(y)
res = x;
names = fieldnames(y);
for fnum = 1:numel(names)
if isfield(x,names{fnum})
res.(names{fnum}) = mergeStructs(x.(names{fnum}),y.(names{fnum}));
else
res.(names{fnum}) = y.(names{fnum});
end
end
else
res = y;
end
Then res = mergeStructs(x,y); gives:
>> res.a
ans =
4
>> res.b
ans =
c: 2
d: 3
as you require.
EDIT: I added isstruct(x) && to the first line. The old version worked fine because isfield(x,n) returns 0 if ~isstruct(x), but the new version is slightly faster if y is a big struct and ~isstruct(x).