TypeError in SuggestionController#index

nil can't be coerced into Fixnum

Extracted source (around line #112):
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value = 0
@all_degrees.each do |degree|
value = value + (matrix[degree.id][discipline.id] * user_rating[degree.id])
end
user_liked_discipline[discipline.id] = value
end

Rails.root: /app

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Request

Parameters:

None

Response

Headers:

None