Add function to validate profile values (#25)

Co-authored-by: Abel Soares Siqueira <nepper271@gmail.com>

Author: datejada

src/model.jl

@@ -3,7 +3,7 @@ export find_solution, find_search_interval
 """
     (a, b) = find_search_interval(f)
 
-Returns an interval such that ``f(a) × f(b) ≯ 0``.
+Returns an interval such that ``f(a) × f(b) ≤ 0``.
 It could be 0 for either endpoint, but it is not positive,
 ensuring that there is a root in `[a, b]`.
 """
@@ -32,6 +32,7 @@ S(x) = \\frac{1}{|P|} \\sum_{p ∈ P:\\ p > 0} p^x.
 If not possible, return either 0 or 1000, depending on what is most appropriate.
 """
 function find_solution(P, μ)
+    validate_profile(P)
     σ(P, x) = P > 0 ? P^x : 0.0
     S(P, x) = mean(σ.(P, x))
     m = length(P)
@@ -46,3 +47,14 @@ function find_solution(P, μ)
         return 1000.0
     end
 end
+
+"""
+    validate_profile(P)
+
+Validates if the values of profile P are within 0 and 1. If not, throws an error message and stops the calculation.
+"""
+function validate_profile(P)
+    if !all(0 .≤ P .≤ 1)
+        error("Profile values must be within 0 and 1. Calculation stopped.")
+    end
+end

test/runtests.jl

@@ -25,8 +25,15 @@ function test_fit_profile()
     @test find_solution(profile_values, target_mean) ≈ expected_coefficient atol = 1e-3
 end
 
+function test_throws_error()
+    profile_values = [-0.5, 0.2, 0.8, 1.5]
+    target_mean = 0.5
+    @test_throws ErrorException find_solution(profile_values, target_mean)
+end
+
 @testset "TulipaProfileFitting" begin
     @testset "fit_profile" begin
         test_fit_profile()
+        test_throws_error()
     end
 end